diff --git a/docs/_toc.yml b/docs/_toc.yml
index 829540d32..d3d3152be 100644
--- a/docs/_toc.yml
+++ b/docs/_toc.yml
@@ -43,6 +43,7 @@ parts:
- file: friedland/chapter_9.ipynb
- file: friedland/chapter_10.ipynb
- file: friedland/chapter_11.ipynb
+ - file: friedland/chapter_12.ipynb
- file: friedland/chapter_15_monitoring.ipynb
- chapters:
- file: gallery/index.md
diff --git a/docs/friedland/chapter_12.ipynb b/docs/friedland/chapter_12.ipynb
new file mode 100644
index 000000000..67963bb54
--- /dev/null
+++ b/docs/friedland/chapter_12.ipynb
@@ -0,0 +1,5196 @@
+{
+ "cells": [
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_1",
+ "metadata": {},
+ "source": [
+ "# Chapter 12 - Case Outstanding Development Technique\n",
+ "\n",
+ "> \"The case outstanding development technique is used to estimate future development on known claims (i.e., case outstanding development). The method can also be used to estimate total unpaid claims, including both development on known claims and pure IBNR... In this chapter, we refer to this technique as Approach #1. We also present an example for a self-insurer of the standard development technique applied to case outstanding in which the case outstanding development factors to ultimate are derived from industry-based benchmark reported and paid claim development factors; we refer to this example as Approach #2.\"\n",
+ "> -- Friedland, Chapter 12\n",
+ "\n",
+ "This notebook reconciles the exhibits from Friedland Chapter 12:\n",
+ "- **Exhibit I**: U.S. Industry Auto (Approach #1) - Sheets 1 through 5\n",
+ "- **Exhibit II**: XYZ Insurer - Auto BI (Approach #1) - Sheets 1 through 7\n",
+ "- **Exhibit III**: Self-Insurer Case Outstanding Only - General Liability (Approach #2)\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 1,
+ "id": "cell_code_2",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:32.825162Z",
+ "iopub.status.busy": "2026-09-28T14:20:32.824487Z",
+ "iopub.status.idle": "2026-09-28T14:20:35.870108Z",
+ "shell.execute_reply": "2026-09-28T14:20:35.869116Z"
+ }
+ },
+ "outputs": [],
+ "source": [
+ "import numpy as np\n",
+ "import pandas as pd\n",
+ "import chainladder as cl\n",
+ "import warnings\n",
+ "from IPython.display import display as nb_display\n",
+ "\n",
+ "# Suppress minor warnings for clean presentation\n",
+ "warnings.filterwarnings(\"ignore\")\n",
+ "\n",
+ "\n",
+ "def format_exh(\n",
+ " exh_df: pd.DataFrame,\n",
+ " value_cols: list[str] = [],\n",
+ " factor_cols: list[str] = [],\n",
+ " other_formats: dict = {},\n",
+ " origin_format: str = \"{:%Y}\",\n",
+ " origin_name: str = \"Accident Year\",\n",
+ " total_cols: list[str] = [],\n",
+ "):\n",
+ " \"\"\"\n",
+ " Actuarial exhibit styler matching Chapter 11.\n",
+ " Adds column numbering (1), (2), ..., currency/factor formatting, and summary totals.\n",
+ " \"\"\"\n",
+ "\n",
+ " def _format(\n",
+ " df: pd.DataFrame,\n",
+ " val_c: list[str] = [],\n",
+ " fac_c: list[str] = [],\n",
+ " oth_f: dict = {},\n",
+ " orig_f: str = None,\n",
+ " orig_n: str = origin_name,\n",
+ " ):\n",
+ " idx_name = df.index.name if df.index.name else \"index\"\n",
+ " format_dict = {}\n",
+ " if orig_f:\n",
+ " format_dict[orig_n] = orig_f\n",
+ " format_dict.update({x: \"{:,.0f}\" for x in val_c})\n",
+ " format_dict.update({x: \"{:,.3f}\" for x in fac_c})\n",
+ " format_dict.update(oth_f)\n",
+ "\n",
+ " return (\n",
+ " df\n",
+ " .reset_index()\n",
+ " .rename(columns={idx_name: orig_n})\n",
+ " .style.hide(axis=\"index\")\n",
+ " .set_properties(**{\"text-align\": \"right\"})\n",
+ " .format(format_dict)\n",
+ " )\n",
+ "\n",
+ " col_idx = pd.DataFrame(\n",
+ " [[f\"({i + 2})\" for i in range(len(exh_df.columns))]],\n",
+ " columns=exh_df.columns,\n",
+ " index=[\"(1)\"],\n",
+ " )\n",
+ " table_styler = _format(col_idx, orig_f=None, orig_n=origin_name).concat(\n",
+ " _format(\n",
+ " exh_df,\n",
+ " val_c=value_cols,\n",
+ " fac_c=factor_cols,\n",
+ " oth_f=other_formats,\n",
+ " orig_f=origin_format,\n",
+ " orig_n=origin_name,\n",
+ " )\n",
+ " )\n",
+ "\n",
+ " if len(total_cols) > 0:\n",
+ " table_styler = table_styler.concat(\n",
+ " _format(\n",
+ " exh_df.agg([\"sum\"]).rename(index={\"sum\": \"Total\"}),\n",
+ " val_c=value_cols,\n",
+ " fac_c=factor_cols,\n",
+ " oth_f={x: \"\" for x in exh_df.columns if x not in total_cols},\n",
+ " orig_f=None,\n",
+ " orig_n=origin_name,\n",
+ " )\n",
+ " )\n",
+ " return table_styler"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_3",
+ "metadata": {},
+ "source": [
+ "## Exhibit I Analysis\n",
+ "\n",
+ "In Exhibit I, Friedland demonstrates **Approach #1** using the U.S. Industry Auto dataset (`usauto`). This technique estimates unpaid claims by analyzing the historical relationships of incremental paid claims and case reserve runoff to prior carried case reserves.\n",
+ "\n",
+ "Following the design pattern established in **Chapter 11**, we fit our dedicated `cl.CaseOutstanding` models upfront to power the subsequent exhibits.\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_4",
+ "metadata": {},
+ "source": [
+ "## Exhibit I Sheet 1\n",
+ "\n",
+ "### Case Outstanding and Incremental Paid Claims ($000)\n",
+ "\n",
+ "- **Case Outstanding**: Calculated dynamically as $\\text{Case Outstanding} = \\text{Reported Claims} - \\text{Paid Claims}$.\n",
+ "- **Incremental Paid Claims**: Derived dynamically from Cumulative Paid Claims via `.cum_to_incr()`.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "id": "cell_code_5",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:35.873747Z",
+ "iopub.status.busy": "2026-09-28T14:20:35.873014Z",
+ "iopub.status.idle": "2026-09-28T14:20:36.518620Z",
+ "shell.execute_reply": "2026-09-28T14:20:36.517472Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "PART 1 - Case Outstanding Triangle as of (months) ($000):\n"
+ ]
+ },
+ {
+ "data": {
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+ " | \n",
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\n",
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+ " 1,634,690 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
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\n",
+ " \n",
+ " | 2004 | \n",
+ " 21,047,539 | \n",
+ " 11,150,459 | \n",
+ " 6,316,995 | \n",
+ " 3,201,985 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 21,260,172 | \n",
+ " 11,087,832 | \n",
+ " 6,141,416 | \n",
+ " | \n",
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+ " | \n",
+ " | \n",
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+ " | \n",
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+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 21,623,594 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
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+ ],
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+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "PART 2 - Incremental Paid Claims Triangle as of (months) ($000):\n"
+ ]
+ },
+ {
+ "data": {
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\n",
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+ " | \n",
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+ " | \n",
+ " | \n",
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\n",
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+ " | \n",
+ " | \n",
+ " | \n",
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+ " | \n",
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\n",
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+ " | \n",
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+ ],
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+ ""
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+ }
+ ],
+ "source": [
+ "usauto = cl.load_sample(\"usauto\")\n",
+ "paid_cumulative = usauto[\"paid\"]\n",
+ "incurred = usauto[\"incurred\"]\n",
+ "\n",
+ "# 1. Triangle of Case Outstanding ($000)\n",
+ "case_outstanding = incurred - paid_cumulative\n",
+ "\n",
+ "# 2. Triangle of Incremental Paid Claims ($000)\n",
+ "incremental_paid = paid_cumulative.cum_to_incr()\n",
+ "\n",
+ "# - m_all: fits with all historical origin periods for review\n",
+ "# - m_5: fits 5-year averages\n",
+ "# - m_3: fits 3-year averages (used for selected ratios)\n",
+ "m_all = cl.CaseOutstanding(\n",
+ " paid_to_incurred=(\"paid\", \"incurred\"), paid_n_periods=-1, case_n_periods=-1\n",
+ ").fit(usauto)\n",
+ "m_5 = cl.CaseOutstanding(\n",
+ " paid_to_incurred=(\"paid\", \"incurred\"), paid_n_periods=5, case_n_periods=5\n",
+ ").fit(usauto)\n",
+ "m_3 = cl.CaseOutstanding(\n",
+ " paid_to_incurred=(\"paid\", \"incurred\"), paid_n_periods=3, case_n_periods=3\n",
+ ").fit(usauto)\n",
+ "\n",
+ "print(\"PART 1 - Case Outstanding Triangle as of (months) ($000):\")\n",
+ "nb_display(case_outstanding.style.format(\"{:,.0f}\", na_rep=\"\"))\n",
+ "\n",
+ "print(\"\\nPART 2 - Incremental Paid Claims Triangle as of (months) ($000):\")\n",
+ "nb_display(incremental_paid.style.format(\"{:,.0f}\", na_rep=\"\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_6",
+ "metadata": {},
+ "source": [
+ "## Exhibit I Sheet 2\n",
+ "\n",
+ "### Ratio of Incremental Paid Claims to Previous Case Outstanding\n",
+ "\n",
+ "This sheet presents:\n",
+ "- **PART 1 - Ratio Triangle**: Evaluated natively via `cl.CaseOutstanding.paid_to_prior_case_`, calculating the proportion of previous case reserves paid out during each subsequent development lag:\n",
+ " $$\\text{Ratio}_{d} = \\frac{\\text{Incremental Paid}_{d}}{\\text{Case Outstanding}_{d-12}}$$\n",
+ "- **PART 2 - Historical Averages**: Summary table combining the Latest 5 Years (`m_5.paid_ldf_`), Latest 3 Years (`m_3.paid_ldf_`), and 5-Year Medial (5x1).\n",
+ "- **PART 3 - Selected Ratios**: Actuarial selections based on the Latest 3 Years average with **To Ult = 1.100**.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 3,
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+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "PART 1 - Ratio of Incremental Paid Claims to Previous Case Outstanding (cl.Triangle):\n"
+ ]
+ },
+ {
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+ " 24-36 36-48 48-60 60-72 72-84 84-96 96-108 108-120 120-132\n",
+ "1998 0.795 0.687 0.695 0.693 0.603 0.594 0.546 0.447 0.524\n",
+ "1999 0.846 0.720 0.693 0.670 0.627 0.606 0.571 0.428 NaN\n",
+ "2000 0.885 0.713 0.699 0.675 0.641 0.646 0.544 NaN NaN\n",
+ "2001 0.882 0.731 0.729 0.743 0.663 0.642 NaN NaN NaN\n",
+ "2002 0.857 0.726 0.718 0.717 0.654 NaN NaN NaN NaN\n",
+ "2003 0.821 0.691 0.705 0.684 NaN NaN NaN NaN NaN\n",
+ "2004 0.813 0.695 0.718 NaN NaN NaN NaN NaN NaN\n",
+ "2005 0.828 0.716 NaN NaN NaN NaN NaN NaN NaN\n",
+ "2006 0.858 NaN NaN NaN NaN NaN NaN NaN NaN\n",
+ "2007 NaN NaN NaN NaN NaN NaN NaN NaN NaN"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "PART 2 - Historical Averages of the Ratio:\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 24-36 | \n",
+ " 36-48 | \n",
+ " 48-60 | \n",
+ " 60-72 | \n",
+ " 72-84 | \n",
+ " 84-96 | \n",
+ " 96-108 | \n",
+ " 108-120 | \n",
+ " 120-132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | Latest 5 Years | \n",
+ " 0.836 | \n",
+ " 0.712 | \n",
+ " 0.714 | \n",
+ " 0.698 | \n",
+ " 0.638 | \n",
+ " 0.622 | \n",
+ " 0.553 | \n",
+ " 0.437 | \n",
+ " 0.524 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | Latest 3 Years | \n",
+ " 0.833 | \n",
+ " 0.701 | \n",
+ " 0.714 | \n",
+ " 0.714 | \n",
+ " 0.653 | \n",
+ " 0.631 | \n",
+ " 0.553 | \n",
+ " 0.437 | \n",
+ " 0.524 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 5-Year Medial (5x1) | \n",
+ " 0.835 | \n",
+ " 0.712 | \n",
+ " 0.714 | \n",
+ " 0.692 | \n",
+ " 0.641 | \n",
+ " 0.624 | \n",
+ " 0.546 | \n",
+ " 0.437 | \n",
+ " 0.524 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ "
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+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "PART 3 - Selected Ratio of Incremental Paid Claims to Previous Case Outstanding:\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | Selected | \n",
+ " 0.833 | \n",
+ " 0.701 | \n",
+ " 0.714 | \n",
+ " 0.714 | \n",
+ " 0.653 | \n",
+ " 0.631 | \n",
+ " 0.553 | \n",
+ " 0.437 | \n",
+ " 0.524 | \n",
+ " 1.100 | \n",
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+ "
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+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "print(\n",
+ " \"PART 1 - Ratio of Incremental Paid Claims to Previous Case Outstanding (cl.Triangle):\"\n",
+ ")\n",
+ "tri_paid = m_all.paid_to_prior_case_\n",
+ "nb_display(tri_paid.round(3))\n",
+ "\n",
+ "print(\"\\nPART 2 - Historical Averages of the Ratio:\")\n",
+ "df_paid = tri_paid.to_frame(origin_as_datetime=False)\n",
+ "\n",
+ "\n",
+ "def calc_medial_5x1(s):\n",
+ " vals = s.dropna().tail(5).values\n",
+ " if len(vals) > 2:\n",
+ " return np.sort(vals)[1:-1].mean()\n",
+ " elif len(vals) > 0:\n",
+ " return vals.mean()\n",
+ " return np.nan\n",
+ "\n",
+ "\n",
+ "medial_5x1_paid = df_paid.apply(calc_medial_5x1)\n",
+ "\n",
+ "averages_paid_df = pd.DataFrame({\n",
+ " \"Latest 5 Years\": m_5.paid_ldf_.to_frame().iloc[0],\n",
+ " \"Latest 3 Years\": m_3.paid_ldf_.to_frame().iloc[0],\n",
+ " \"5-Year Medial (5x1)\": medial_5x1_paid,\n",
+ "}).T\n",
+ "averages_paid_df[\"To Ult\"] = np.nan\n",
+ "nb_display(averages_paid_df.style.format(\"{:.3f}\", na_rep=\"\"))\n",
+ "\n",
+ "print(\n",
+ " \"\\nPART 3 - Selected Ratio of Incremental Paid Claims to Previous Case Outstanding:\"\n",
+ ")\n",
+ "dev_cols_e1 = [24, 36, 48, 60, 72, 84, 96, 108, 120]\n",
+ "selected_paid_ratios = pd.Series(m_3.paid_ldf_.values[0, 0, 0, :], index=dev_cols_e1)\n",
+ "selected_paid_ratios[\"To Ult\"] = 1.100\n",
+ "selected_paid_df = pd.DataFrame([selected_paid_ratios], index=[\"Selected\"])\n",
+ "nb_display(selected_paid_df.style.format(\"{:.3f}\", na_rep=\"\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_8",
+ "metadata": {},
+ "source": [
+ "## Exhibit I Sheet 3\n",
+ "\n",
+ "### Ratio of Case Outstanding to Previous Case Outstanding\n",
+ "\n",
+ "This sheet presents:\n",
+ "- **PART 1 - Ratio Triangle**: Evaluated natively via `cl.CaseOutstanding.case_to_prior_case_`, calculating the proportion of case reserves remaining after each subsequent development lag:\n",
+ " $$\\text{Ratio}_{d} = \\frac{\\text{Case Outstanding}_{d}}{\\text{Case Outstanding}_{d-12}}$$\n",
+ "- **PART 2 - Historical Averages**: Summary table combining the Latest 5 Years (`m_5.case_ldf_`), Latest 3 Years (`m_3.case_ldf_`), and 5-Year Medial (5x1).\n",
+ "- **PART 3 - Selected Ratios**: Actuarial selections based on the Latest 3 Years average with **To Ult = 0.000**.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 4,
+ "id": "cell_code_9",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:36.579502Z",
+ "iopub.status.busy": "2026-09-28T14:20:36.578999Z",
+ "iopub.status.idle": "2026-09-28T14:20:36.627293Z",
+ "shell.execute_reply": "2026-09-28T14:20:36.626550Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "PART 1 - Ratio of Case Outstanding to Previous Case Outstanding (cl.Triangle):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ " \n",
+ " \n",
+ " | \n",
+ " 24-36 | \n",
+ " 36-48 | \n",
+ " 48-60 | \n",
+ " 60-72 | \n",
+ " 72-84 | \n",
+ " 84-96 | \n",
+ " 96-108 | \n",
+ " 108-120 | \n",
+ " 120-132 | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " 0.5380 | \n",
+ " 0.5540 | \n",
+ " 0.5250 | \n",
+ " 0.4980 | \n",
+ " 0.5330 | \n",
+ " 0.5380 | \n",
+ " 0.5880 | \n",
+ " 0.6970 | \n",
+ " 0.5800 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " 0.5370 | \n",
+ " 0.5650 | \n",
+ " 0.5440 | \n",
+ " 0.4970 | \n",
+ " 0.5030 | \n",
+ " 0.5800 | \n",
+ " 0.6420 | \n",
+ " 0.6510 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 0.5460 | \n",
+ " 0.5740 | \n",
+ " 0.5390 | \n",
+ " 0.4870 | \n",
+ " 0.5380 | \n",
+ " 0.5430 | \n",
+ " 0.6660 | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 0.5410 | \n",
+ " 0.5660 | \n",
+ " 0.5150 | \n",
+ " 0.5010 | \n",
+ " 0.5080 | \n",
+ " 0.5410 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 0.5410 | \n",
+ " 0.5550 | \n",
+ " 0.5410 | \n",
+ " 0.4800 | \n",
+ " 0.4880 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 0.5270 | \n",
+ " 0.5770 | \n",
+ " 0.5360 | \n",
+ " 0.4760 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 0.5300 | \n",
+ " 0.5670 | \n",
+ " 0.5070 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 0.5220 | \n",
+ " 0.5540 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 0.5260 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ "
"
+ ],
+ "text/plain": [
+ " 24-36 36-48 48-60 60-72 72-84 84-96 96-108 108-120 120-132\n",
+ "1998 0.538 0.554 0.525 0.498 0.533 0.538 0.588 0.697 0.58\n",
+ "1999 0.537 0.565 0.544 0.497 0.503 0.580 0.642 0.651 NaN\n",
+ "2000 0.546 0.574 0.539 0.487 0.538 0.543 0.666 NaN NaN\n",
+ "2001 0.541 0.566 0.515 0.501 0.508 0.541 NaN NaN NaN\n",
+ "2002 0.541 0.555 0.541 0.480 0.488 NaN NaN NaN NaN\n",
+ "2003 0.527 0.577 0.536 0.476 NaN NaN NaN NaN NaN\n",
+ "2004 0.530 0.567 0.507 NaN NaN NaN NaN NaN NaN\n",
+ "2005 0.522 0.554 NaN NaN NaN NaN NaN NaN NaN\n",
+ "2006 0.526 NaN NaN NaN NaN NaN NaN NaN NaN\n",
+ "2007 NaN NaN NaN NaN NaN NaN NaN NaN NaN"
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "PART 2 - Historical Averages of the Ratio:\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 24-36 | \n",
+ " 36-48 | \n",
+ " 48-60 | \n",
+ " 60-72 | \n",
+ " 72-84 | \n",
+ " 84-96 | \n",
+ " 96-108 | \n",
+ " 108-120 | \n",
+ " 120-132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | Latest 5 Years | \n",
+ " 0.529 | \n",
+ " 0.564 | \n",
+ " 0.528 | \n",
+ " 0.488 | \n",
+ " 0.514 | \n",
+ " 0.551 | \n",
+ " 0.632 | \n",
+ " 0.674 | \n",
+ " 0.580 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | Latest 3 Years | \n",
+ " 0.526 | \n",
+ " 0.566 | \n",
+ " 0.528 | \n",
+ " 0.486 | \n",
+ " 0.511 | \n",
+ " 0.555 | \n",
+ " 0.632 | \n",
+ " 0.674 | \n",
+ " 0.580 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 5-Year Medial (5x1) | \n",
+ " 0.527 | \n",
+ " 0.562 | \n",
+ " 0.530 | \n",
+ " 0.488 | \n",
+ " 0.515 | \n",
+ " 0.542 | \n",
+ " 0.642 | \n",
+ " 0.674 | \n",
+ " 0.580 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ "
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+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "PART 3 - Selected Ratio of Case Outstanding to Previous Case Outstanding:\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | Selected | \n",
+ " 0.526 | \n",
+ " 0.566 | \n",
+ " 0.528 | \n",
+ " 0.486 | \n",
+ " 0.511 | \n",
+ " 0.555 | \n",
+ " 0.632 | \n",
+ " 0.674 | \n",
+ " 0.580 | \n",
+ " 0.000 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "print(\"PART 1 - Ratio of Case Outstanding to Previous Case Outstanding (cl.Triangle):\")\n",
+ "tri_case = m_all.case_to_prior_case_\n",
+ "nb_display(tri_case.round(3))\n",
+ "\n",
+ "print(\"\\nPART 2 - Historical Averages of the Ratio:\")\n",
+ "df_case = tri_case.to_frame(origin_as_datetime=False)\n",
+ "medial_5x1_case = df_case.apply(calc_medial_5x1)\n",
+ "\n",
+ "averages_case_df = pd.DataFrame({\n",
+ " \"Latest 5 Years\": m_5.case_ldf_.to_frame().iloc[0],\n",
+ " \"Latest 3 Years\": m_3.case_ldf_.to_frame().iloc[0],\n",
+ " \"5-Year Medial (5x1)\": medial_5x1_case,\n",
+ "}).T\n",
+ "averages_case_df[\"To Ult\"] = np.nan\n",
+ "nb_display(averages_case_df.style.format(\"{:.3f}\", na_rep=\"\"))\n",
+ "\n",
+ "print(\"\\nPART 3 - Selected Ratio of Case Outstanding to Previous Case Outstanding:\")\n",
+ "selected_case_ratios = pd.Series(m_3.case_ldf_.values[0, 0, 0, :], index=dev_cols_e1)\n",
+ "selected_case_ratios[\"To Ult\"] = 0.000\n",
+ "selected_case_df = pd.DataFrame([selected_case_ratios], index=[\"Selected\"])\n",
+ "nb_display(selected_case_df.style.format(\"{:.3f}\", na_rep=\"\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_10",
+ "metadata": {},
+ "source": [
+ "## Exhibit I Sheet 4\n",
+ "\n",
+ "### Projection of Paid Claims ($000)\n",
+ "\n",
+ "Using the selected ratios:\n",
+ "1. **Complete the Square of Case Outstanding**:\n",
+ " $$\\text{Case}_{d} = \\text{Case}_{d-12} \\times \\text{Selected Case Ratio}_{d}$$\n",
+ "2. **Complete the Square of Incremental Paid Claims**:\n",
+ " $$\\text{Incr Paid}_{d} = \\text{Case}_{d-12} \\times \\text{Selected Paid Ratio}_{d}$$\n",
+ " $$\\text{Incr Paid}_{\\text{To Ult}} = \\text{Case}_{120} \\times \\text{Selected Paid Ratio}_{\\text{To Ult}}$$\n",
+ "3. **Cumulative Paid Claims**: Cumulative sum across development lags through `To Ult`.\n",
+ "\n",
+ "Projected cells beyond the latest diagonal are highlighted in light blue (`#d1ecf1`).\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 5,
+ "id": "cell_code_11",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:36.630186Z",
+ "iopub.status.busy": "2026-09-28T14:20:36.629767Z",
+ "iopub.status.idle": "2026-09-28T14:20:36.738951Z",
+ "shell.execute_reply": "2026-09-28T14:20:36.738148Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "1. Case Outstanding as of (months) ($000) [Projected cells highlighted]:"
+ ]
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 12 | \n",
+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " 18,478,233 | \n",
+ " 9,937,970 | \n",
+ " 5,506,911 | \n",
+ " 2,892,519 | \n",
+ " 1,440,783 | \n",
+ " 767,842 | \n",
+ " 413,097 | \n",
+ " 242,778 | \n",
+ " 169,222 | \n",
+ " 98,117 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " 18,544,291 | \n",
+ " 9,955,034 | \n",
+ " 5,623,522 | \n",
+ " 3,060,431 | \n",
+ " 1,520,760 | \n",
+ " 764,736 | \n",
+ " 443,528 | \n",
+ " 284,732 | \n",
+ " 185,233 | \n",
+ " 107,400 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 19,034,933 | \n",
+ " 10,395,464 | \n",
+ " 5,969,194 | \n",
+ " 3,217,937 | \n",
+ " 1,567,806 | \n",
+ " 842,849 | \n",
+ " 457,854 | \n",
+ " 304,704 | \n",
+ " 205,306 | \n",
+ " 119,039 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 19,401,810 | \n",
+ " 10,487,914 | \n",
+ " 5,936,461 | \n",
+ " 3,056,202 | \n",
+ " 1,532,147 | \n",
+ " 777,926 | \n",
+ " 421,141 | \n",
+ " 266,046 | \n",
+ " 179,258 | \n",
+ " 103,936 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 20,662,461 | \n",
+ " 11,176,330 | \n",
+ " 6,198,509 | \n",
+ " 3,350,967 | \n",
+ " 1,609,188 | \n",
+ " 785,497 | \n",
+ " 435,836 | \n",
+ " 275,329 | \n",
+ " 185,513 | \n",
+ " 107,563 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 21,078,651 | \n",
+ " 11,098,119 | \n",
+ " 6,398,219 | \n",
+ " 3,431,210 | \n",
+ " 1,634,690 | \n",
+ " 835,581 | \n",
+ " 463,625 | \n",
+ " 292,884 | \n",
+ " 197,342 | \n",
+ " 114,421 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 21,047,539 | \n",
+ " 11,150,459 | \n",
+ " 6,316,995 | \n",
+ " 3,201,985 | \n",
+ " 1,556,120 | \n",
+ " 795,419 | \n",
+ " 441,341 | \n",
+ " 278,807 | \n",
+ " 187,857 | \n",
+ " 108,922 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 21,260,172 | \n",
+ " 11,087,832 | \n",
+ " 6,141,416 | \n",
+ " 3,242,194 | \n",
+ " 1,575,661 | \n",
+ " 805,407 | \n",
+ " 446,883 | \n",
+ " 282,308 | \n",
+ " 190,216 | \n",
+ " 110,289 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 20,973,908 | \n",
+ " 11,034,842 | \n",
+ " 6,241,767 | \n",
+ " 3,295,171 | \n",
+ " 1,601,407 | \n",
+ " 818,568 | \n",
+ " 454,185 | \n",
+ " 286,921 | \n",
+ " 193,324 | \n",
+ " 112,091 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 21,623,594 | \n",
+ " 11,369,888 | \n",
+ " 6,431,282 | \n",
+ " 3,395,221 | \n",
+ " 1,650,030 | \n",
+ " 843,422 | \n",
+ " 467,976 | \n",
+ " 295,632 | \n",
+ " 199,193 | \n",
+ " 115,495 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "2. Incremental Paid Claims as of (months) ($000) [Projected cells highlighted]:\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 12 | \n",
+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " 18,539,254 | \n",
+ " 14,691,785 | \n",
+ " 6,830,969 | \n",
+ " 3,830,031 | \n",
+ " 2,004,496 | \n",
+ " 868,887 | \n",
+ " 455,900 | \n",
+ " 225,555 | \n",
+ " 108,579 | \n",
+ " 88,731 | \n",
+ " 107,929 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " 20,410,193 | \n",
+ " 15,680,491 | \n",
+ " 7,168,718 | \n",
+ " 3,899,839 | \n",
+ " 2,049,291 | \n",
+ " 953,511 | \n",
+ " 463,714 | \n",
+ " 253,051 | \n",
+ " 121,726 | \n",
+ " 97,126 | \n",
+ " 118,140 | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 22,120,843 | \n",
+ " 16,855,171 | \n",
+ " 7,413,268 | \n",
+ " 4,173,103 | \n",
+ " 2,172,895 | \n",
+ " 1,004,821 | \n",
+ " 544,233 | \n",
+ " 248,891 | \n",
+ " 133,269 | \n",
+ " 107,651 | \n",
+ " 130,943 | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 22,992,259 | \n",
+ " 17,103,939 | \n",
+ " 7,671,637 | \n",
+ " 4,326,081 | \n",
+ " 2,269,520 | \n",
+ " 1,015,365 | \n",
+ " 499,620 | \n",
+ " 233,053 | \n",
+ " 116,361 | \n",
+ " 93,994 | \n",
+ " 114,330 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 24,092,782 | \n",
+ " 17,702,531 | \n",
+ " 8,108,490 | \n",
+ " 4,449,081 | \n",
+ " 2,401,492 | \n",
+ " 1,052,839 | \n",
+ " 495,995 | \n",
+ " 241,185 | \n",
+ " 120,421 | \n",
+ " 97,273 | \n",
+ " 118,319 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 24,084,451 | \n",
+ " 17,315,161 | \n",
+ " 7,670,720 | \n",
+ " 4,513,869 | \n",
+ " 2,346,453 | \n",
+ " 1,066,844 | \n",
+ " 527,620 | \n",
+ " 256,563 | \n",
+ " 128,100 | \n",
+ " 103,475 | \n",
+ " 125,863 | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 24,369,770 | \n",
+ " 17,120,093 | \n",
+ " 7,746,815 | \n",
+ " 4,537,994 | \n",
+ " 2,287,399 | \n",
+ " 1,015,567 | \n",
+ " 502,260 | \n",
+ " 244,231 | \n",
+ " 121,943 | \n",
+ " 98,502 | \n",
+ " 119,814 | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 25,100,697 | \n",
+ " 17,601,532 | \n",
+ " 7,942,765 | \n",
+ " 4,384,220 | \n",
+ " 2,316,123 | \n",
+ " 1,028,320 | \n",
+ " 508,568 | \n",
+ " 247,298 | \n",
+ " 123,474 | \n",
+ " 99,739 | \n",
+ " 121,318 | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 25,608,776 | \n",
+ " 17,997,721 | \n",
+ " 7,732,760 | \n",
+ " 4,455,858 | \n",
+ " 2,353,968 | \n",
+ " 1,045,123 | \n",
+ " 516,877 | \n",
+ " 251,339 | \n",
+ " 125,491 | \n",
+ " 101,369 | \n",
+ " 123,301 | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 27,229,969 | \n",
+ " 18,015,429 | \n",
+ " 7,967,546 | \n",
+ " 4,591,149 | \n",
+ " 2,425,441 | \n",
+ " 1,076,855 | \n",
+ " 532,571 | \n",
+ " 258,971 | \n",
+ " 129,302 | \n",
+ " 104,446 | \n",
+ " 127,044 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "3. Cumulative Paid Claims as of (months) ($000):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
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+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " 18,539,254 | \n",
+ " 33,231,039 | \n",
+ " 40,062,008 | \n",
+ " 43,892,039 | \n",
+ " 45,896,535 | \n",
+ " 46,765,422 | \n",
+ " 47,221,322 | \n",
+ " 47,446,877 | \n",
+ " 47,555,456 | \n",
+ " 47,644,187 | \n",
+ " 47,752,116 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " 20,410,193 | \n",
+ " 36,090,684 | \n",
+ " 43,259,402 | \n",
+ " 47,159,241 | \n",
+ " 49,208,532 | \n",
+ " 50,162,043 | \n",
+ " 50,625,757 | \n",
+ " 50,878,808 | \n",
+ " 51,000,534 | \n",
+ " 51,097,660 | \n",
+ " 51,215,801 | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 22,120,843 | \n",
+ " 38,976,014 | \n",
+ " 46,389,282 | \n",
+ " 50,562,385 | \n",
+ " 52,735,280 | \n",
+ " 53,740,101 | \n",
+ " 54,284,334 | \n",
+ " 54,533,225 | \n",
+ " 54,666,494 | \n",
+ " 54,774,146 | \n",
+ " 54,905,089 | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 22,992,259 | \n",
+ " 40,096,198 | \n",
+ " 47,767,835 | \n",
+ " 52,093,916 | \n",
+ " 54,363,436 | \n",
+ " 55,378,801 | \n",
+ " 55,878,421 | \n",
+ " 56,111,474 | \n",
+ " 56,227,835 | \n",
+ " 56,321,829 | \n",
+ " 56,436,159 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 24,092,782 | \n",
+ " 41,795,313 | \n",
+ " 49,903,803 | \n",
+ " 54,352,884 | \n",
+ " 56,754,376 | \n",
+ " 57,807,215 | \n",
+ " 58,303,210 | \n",
+ " 58,544,395 | \n",
+ " 58,664,817 | \n",
+ " 58,762,090 | \n",
+ " 58,880,409 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 24,084,451 | \n",
+ " 41,399,612 | \n",
+ " 49,070,332 | \n",
+ " 53,584,201 | \n",
+ " 55,930,654 | \n",
+ " 56,997,498 | \n",
+ " 57,525,118 | \n",
+ " 57,781,681 | \n",
+ " 57,909,781 | \n",
+ " 58,013,256 | \n",
+ " 58,139,120 | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 24,369,770 | \n",
+ " 41,489,863 | \n",
+ " 49,236,678 | \n",
+ " 53,774,672 | \n",
+ " 56,062,071 | \n",
+ " 57,077,638 | \n",
+ " 57,579,898 | \n",
+ " 57,824,130 | \n",
+ " 57,946,072 | \n",
+ " 58,044,574 | \n",
+ " 58,164,388 | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 25,100,697 | \n",
+ " 42,702,229 | \n",
+ " 50,644,994 | \n",
+ " 55,029,214 | \n",
+ " 57,345,337 | \n",
+ " 58,373,657 | \n",
+ " 58,882,225 | \n",
+ " 59,129,523 | \n",
+ " 59,252,997 | \n",
+ " 59,352,736 | \n",
+ " 59,474,054 | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 25,608,776 | \n",
+ " 43,606,497 | \n",
+ " 51,339,257 | \n",
+ " 55,795,115 | \n",
+ " 58,149,084 | \n",
+ " 59,194,206 | \n",
+ " 59,711,084 | \n",
+ " 59,962,423 | \n",
+ " 60,087,915 | \n",
+ " 60,189,283 | \n",
+ " 60,312,584 | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 27,229,969 | \n",
+ " 45,245,398 | \n",
+ " 53,212,944 | \n",
+ " 57,804,093 | \n",
+ " 60,229,534 | \n",
+ " 61,306,389 | \n",
+ " 61,838,961 | \n",
+ " 62,097,931 | \n",
+ " 62,227,233 | \n",
+ " 62,331,679 | \n",
+ " 62,458,723 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "case_df = case_outstanding.to_frame(origin_as_datetime=False)\n",
+ "case_df.columns = [int(col) for col in case_df.columns]\n",
+ "case_df.index = [int(getattr(idx, \"year\", idx)) for idx in case_df.index]\n",
+ "\n",
+ "incr_paid_df = incremental_paid.to_frame(origin_as_datetime=False)\n",
+ "incr_paid_df.columns = [int(col) for col in incr_paid_df.columns]\n",
+ "incr_paid_df.index = [int(getattr(idx, \"year\", idx)) for idx in incr_paid_df.index]\n",
+ "\n",
+ "# 1. Complete the Square of Case Outstanding\n",
+ "completed_case_df = case_df.copy()\n",
+ "completed_case_df[\"To Ult\"] = 0.0\n",
+ "is_projected_case = pd.DataFrame(\n",
+ " False, index=completed_case_df.index, columns=completed_case_df.columns\n",
+ ")\n",
+ "\n",
+ "for ay in completed_case_df.index:\n",
+ " for d in dev_cols_e1:\n",
+ " if pd.isna(completed_case_df.loc[ay, d]):\n",
+ " prev_case = completed_case_df.loc[ay, d - 12]\n",
+ " completed_case_df.loc[ay, d] = prev_case * selected_case_ratios[d]\n",
+ " is_projected_case.loc[ay, d] = True\n",
+ " completed_case_df.loc[ay, \"To Ult\"] = 0.0\n",
+ " is_projected_case.loc[ay, \"To Ult\"] = True\n",
+ "\n",
+ "# 2. Complete the Square of Incremental Paid Claims\n",
+ "completed_incr_paid_df = incr_paid_df.copy()\n",
+ "completed_incr_paid_df[\"To Ult\"] = np.nan\n",
+ "is_projected_paid = pd.DataFrame(\n",
+ " False, index=completed_incr_paid_df.index, columns=completed_incr_paid_df.columns\n",
+ ")\n",
+ "\n",
+ "for ay in completed_incr_paid_df.index:\n",
+ " for d in dev_cols_e1:\n",
+ " if pd.isna(completed_incr_paid_df.loc[ay, d]):\n",
+ " prev_case = completed_case_df.loc[ay, d - 12]\n",
+ " completed_incr_paid_df.loc[ay, d] = prev_case * selected_paid_ratios[d]\n",
+ " is_projected_paid.loc[ay, d] = True\n",
+ " case_120 = completed_case_df.loc[ay, 120]\n",
+ " completed_incr_paid_df.loc[ay, \"To Ult\"] = case_120 * selected_paid_ratios[\"To Ult\"]\n",
+ " is_projected_paid.loc[ay, \"To Ult\"] = True\n",
+ "\n",
+ "# 3. Cumulative Paid Claims through To Ult\n",
+ "completed_cum_paid_df = completed_incr_paid_df.cumsum(axis=1)\n",
+ "\n",
+ "\n",
+ "# Helper for styling projected cells\n",
+ "def style_projected(df, mask):\n",
+ " return df.style.format(\"{:,.0f}\").apply(\n",
+ " lambda _: np.where(mask, \"background-color: #d1ecf1; font-weight: bold\", \"\"),\n",
+ " axis=None,\n",
+ " )\n",
+ "\n",
+ "\n",
+ "print(\"1. Case Outstanding as of (months) ($000) [Projected cells highlighted]:\")\n",
+ "nb_display(style_projected(completed_case_df, is_projected_case))\n",
+ "\n",
+ "print(\n",
+ " \"\\n2. Incremental Paid Claims as of (months) ($000) [Projected cells highlighted]:\"\n",
+ ")\n",
+ "nb_display(style_projected(completed_incr_paid_df, is_projected_paid))\n",
+ "\n",
+ "print(\"\\n3. Cumulative Paid Claims as of (months) ($000):\")\n",
+ "nb_display(completed_cum_paid_df.style.format(\"{:,.0f}\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_12",
+ "metadata": {},
+ "source": [
+ "## Exhibit I Sheet 5\n",
+ "\n",
+ "### Development of Unpaid Claim Estimate ($000)\n",
+ "\n",
+ "Reconciles the unpaid claim estimate across all accident years using the actuarial exhibit styler (`format_exh`) from **Chapter 11**:\n",
+ "- **(2) Reported Claims**: Latest diagonal of reported claims.\n",
+ "- **(3) Paid Claims**: Latest diagonal of cumulative paid claims.\n",
+ "- **(4) Projected Ultimate**: Cumulative paid claims at `To Ult`.\n",
+ "- **(5) Case Outstanding**: $(2) - (3)$.\n",
+ "- **(6) Estimated IBNR**: $(4) - (2)$.\n",
+ "- **(7) Total Unpaid**: $(4) - (3)$.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 6,
+ "id": "cell_code_13",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:36.741860Z",
+ "iopub.status.busy": "2026-09-28T14:20:36.741545Z",
+ "iopub.status.idle": "2026-09-28T14:20:36.796720Z",
+ "shell.execute_reply": "2026-09-28T14:20:36.795946Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Development of Unpaid Claim Estimate ($000):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | Accident Year | \n",
+ " Reported Claims | \n",
+ " Paid Claims | \n",
+ " Projected Ultimate | \n",
+ " Case Outstanding | \n",
+ " Estimated IBNR | \n",
+ " Total Unpaid | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | (1) | \n",
+ " (2) | \n",
+ " (3) | \n",
+ " (4) | \n",
+ " (5) | \n",
+ " (6) | \n",
+ " (7) | \n",
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+ " \n",
+ "
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+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "sheet5_df = pd.DataFrame(index=case_df.index)\n",
+ "sheet5_df[\"Reported Claims\"] = (\n",
+ " incurred.latest_diagonal.to_frame(origin_as_datetime=False).iloc[:, 0].values\n",
+ ")\n",
+ "sheet5_df[\"Paid Claims\"] = (\n",
+ " paid_cumulative.latest_diagonal.to_frame(origin_as_datetime=False).iloc[:, 0].values\n",
+ ")\n",
+ "sheet5_df[\"Projected Ultimate\"] = completed_cum_paid_df[\"To Ult\"].values\n",
+ "sheet5_df[\"Case Outstanding\"] = sheet5_df[\"Reported Claims\"] - sheet5_df[\"Paid Claims\"]\n",
+ "sheet5_df[\"Estimated IBNR\"] = (\n",
+ " sheet5_df[\"Projected Ultimate\"] - sheet5_df[\"Reported Claims\"]\n",
+ ")\n",
+ "sheet5_df[\"Total Unpaid\"] = sheet5_df[\"Projected Ultimate\"] - sheet5_df[\"Paid Claims\"]\n",
+ "sheet5_df.index = pd.to_datetime(sheet5_df.index.astype(str) + \"-12-31\")\n",
+ "\n",
+ "print(\"Development of Unpaid Claim Estimate ($000):\")\n",
+ "nb_display(\n",
+ " format_exh(\n",
+ " sheet5_df,\n",
+ " value_cols=list(sheet5_df.columns),\n",
+ " total_cols=list(sheet5_df.columns),\n",
+ " origin_name=\"Accident Year\",\n",
+ " origin_format=\"{:%Y}\",\n",
+ " )\n",
+ ")"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_14",
+ "metadata": {},
+ "source": [
+ "---\n",
+ "\n",
+ "## Exhibit II Analysis\n",
+ "\n",
+ "Exhibit II applies the Case Outstanding Development Technique (Approach #1) to the **XYZ Insurer - Auto BI** data.\n",
+ "Because of changing claims operations, settlement rates, and case reserve adequacy noted in previous chapters, the actuary selects the **Latest 2** year averages for development factors, reflecting the most recent operating environment.\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_15",
+ "metadata": {},
+ "source": [
+ "## Exhibit II Sheet 1\n",
+ "\n",
+ "### Case Outstanding and Incremental Paid Claims ($000)\n",
+ "\n",
+ "Source data is loaded from `cl.load_sample(\"friedland_xyz_auto_bi\")`.\n",
+ "- **Case Outstanding**: $\\text{Reported Claims} - \\text{Paid Claims}$.\n",
+ "- **Incremental Paid Claims**: Computed via `.cum_to_incr()`.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 7,
+ "id": "cell_code_16",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:36.800757Z",
+ "iopub.status.busy": "2026-09-28T14:20:36.799211Z",
+ "iopub.status.idle": "2026-09-28T14:20:36.882031Z",
+ "shell.execute_reply": "2026-09-28T14:20:36.880987Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Case Outstanding as of (months) ($000):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
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+ " 48 | \n",
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+ " 72 | \n",
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+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " | \n",
+ " | \n",
+ " 4,862 | \n",
+ " 3,859 | \n",
+ " 3,134 | \n",
+ " 2,447 | \n",
+ " 1,446 | \n",
+ " 1,947 | \n",
+ " 852 | \n",
+ " 71 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " | \n",
+ " 8,589 | \n",
+ " 6,544 | \n",
+ " 5,668 | \n",
+ " 4,346 | \n",
+ " 1,732 | \n",
+ " 1,583 | \n",
+ " 649 | \n",
+ " 479 | \n",
+ " 290 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 14,374 | \n",
+ " 12,236 | \n",
+ " 9,761 | \n",
+ " 9,316 | \n",
+ " 5,458 | \n",
+ " 5,605 | \n",
+ " 3,727 | \n",
+ " 1,603 | \n",
+ " 464 | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 10,288 | \n",
+ " 10,052 | \n",
+ " 8,703 | \n",
+ " 7,969 | \n",
+ " 9,818 | \n",
+ " 6,046 | \n",
+ " 1,471 | \n",
+ " 279 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 10,493 | \n",
+ " 12,438 | \n",
+ " 12,834 | \n",
+ " 15,572 | \n",
+ " 12,469 | \n",
+ " 8,072 | \n",
+ " 3,732 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 7,908 | \n",
+ " 10,755 | \n",
+ " 17,671 | \n",
+ " 17,702 | \n",
+ " 9,726 | \n",
+ " 5,053 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 14,774 | \n",
+ " 30,282 | \n",
+ " 32,916 | \n",
+ " 28,268 | \n",
+ " 17,477 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 25,631 | \n",
+ " 35,213 | \n",
+ " 43,267 | \n",
+ " 30,629 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 23,535 | \n",
+ " 35,005 | \n",
+ " 25,985 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 15,948 | \n",
+ " 19,867 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " 15,223 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "Incremental Paid Claims as of (months) ($000):\n"
+ ]
+ },
+ {
+ "data": {
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+ "\n",
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+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " | \n",
+ " | \n",
+ " 6,309 | \n",
+ " 2,212 | \n",
+ " 1,561 | \n",
+ " 1,538 | \n",
+ " 1,622 | \n",
+ " 1,177 | \n",
+ " 892 | \n",
+ " 453 | \n",
+ " 58 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " | \n",
+ " 4,666 | \n",
+ " 5,195 | \n",
+ " 4,110 | \n",
+ " 4,156 | \n",
+ " 3,905 | \n",
+ " 1,479 | \n",
+ " 635 | \n",
+ " 446 | \n",
+ " 225 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 1,302 | \n",
+ " 5,211 | \n",
+ " 5,626 | \n",
+ " 5,689 | \n",
+ " 6,202 | \n",
+ " 4,823 | \n",
+ " 4,369 | \n",
+ " 2,680 | \n",
+ " 880 | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 1,539 | \n",
+ " 4,413 | \n",
+ " 6,367 | \n",
+ " 6,290 | \n",
+ " 5,778 | \n",
+ " 6,703 | \n",
+ " 5,980 | \n",
+ " 1,449 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 2,318 | \n",
+ " 5,614 | \n",
+ " 5,890 | \n",
+ " 8,273 | \n",
+ " 9,850 | \n",
+ " 8,684 | \n",
+ " 3,808 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 1,743 | \n",
+ " 4,497 | \n",
+ " 6,443 | \n",
+ " 10,209 | \n",
+ " 11,613 | \n",
+ " 4,815 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 2,221 | \n",
+ " 7,677 | \n",
+ " 16,052 | \n",
+ " 17,489 | \n",
+ " 9,372 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 3,043 | \n",
+ " 9,176 | \n",
+ " 14,854 | \n",
+ " 12,953 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 3,531 | \n",
+ " 8,247 | \n",
+ " 11,041 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 3,529 | \n",
+ " 8,336 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " 3,409 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "xyz = cl.load_sample(\"friedland_xyz_auto_bi\")\n",
+ "xyz_rep = xyz[\"Reported Claims\"]\n",
+ "xyz_paid = xyz[\"Paid Claims\"]\n",
+ "\n",
+ "# Raw DataFrames with clean int indexing\n",
+ "xyz_rep_df = xyz_rep.to_frame(origin_as_datetime=False)\n",
+ "xyz_rep_df.columns = [int(c) for c in xyz_rep_df.columns]\n",
+ "xyz_rep_df.index = [int(getattr(i, \"year\", i)) for i in xyz_rep_df.index]\n",
+ "\n",
+ "xyz_paid_df = xyz_paid.to_frame(origin_as_datetime=False)\n",
+ "xyz_paid_df.columns = [int(c) for c in xyz_paid_df.columns]\n",
+ "xyz_paid_df.index = [int(getattr(i, \"year\", i)) for i in xyz_paid_df.index]\n",
+ "\n",
+ "# Case Outstanding Triangle ($000)\n",
+ "# Preserves 0.0 at age 132 for 1998 (15,822 - 15,822 = 0)\n",
+ "xyz_case_df = xyz_rep_df - xyz_paid_df\n",
+ "\n",
+ "# Incremental Paid Claims Triangle ($000)\n",
+ "xyz_incr_paid_df = xyz_paid.cum_to_incr().to_frame(origin_as_datetime=False)\n",
+ "xyz_incr_paid_df.columns = [int(c) for c in xyz_incr_paid_df.columns]\n",
+ "xyz_incr_paid_df.index = [int(getattr(i, \"year\", i)) for i in xyz_incr_paid_df.index]\n",
+ "\n",
+ "print(\"Case Outstanding as of (months) ($000):\")\n",
+ "nb_display(xyz_case_df.style.format(\"{:,.0f}\", na_rep=\"\"))\n",
+ "\n",
+ "print(\"\\nIncremental Paid Claims as of (months) ($000):\")\n",
+ "nb_display(xyz_incr_paid_df.style.format(\"{:,.0f}\", na_rep=\"\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_17",
+ "metadata": {},
+ "source": [
+ "## Exhibit II Sheet 2\n",
+ "\n",
+ "### Ratio of Incremental Paid Claims to Previous Case Outstanding\n",
+ "\n",
+ "Calculates the ratio of incremental payments at age $d$ to case outstanding at age $d-12$:\n",
+ "$$\\text{Ratio}_{d} = \\frac{\\text{Incremental Paid}_{d}}{\\text{Case Outstanding}_{d-12}}$$\n",
+ "\n",
+ "- **Latest 2 Average**: Reflects recent settlement velocity changes.\n",
+ "- **Selected**: Matches the **Latest 2** average across all maturities, with **To Ult = 1.100**.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 8,
+ "id": "cell_code_18",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:36.886648Z",
+ "iopub.status.busy": "2026-09-28T14:20:36.885888Z",
+ "iopub.status.idle": "2026-09-28T14:20:36.935523Z",
+ "shell.execute_reply": "2026-09-28T14:20:36.933022Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Ratio of Incremental Paid Claims to Previous Case Outstanding:"
+ ]
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " | \n",
+ " | \n",
+ " 0.455 | \n",
+ " 0.405 | \n",
+ " 0.491 | \n",
+ " 0.663 | \n",
+ " 0.814 | \n",
+ " 0.458 | \n",
+ " 0.532 | \n",
+ " 0.817 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " | \n",
+ " 0.605 | \n",
+ " 0.628 | \n",
+ " 0.733 | \n",
+ " 0.899 | \n",
+ " 0.854 | \n",
+ " 0.401 | \n",
+ " 0.687 | \n",
+ " 0.470 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 0.363 | \n",
+ " 0.460 | \n",
+ " 0.583 | \n",
+ " 0.666 | \n",
+ " 0.884 | \n",
+ " 0.779 | \n",
+ " 0.719 | \n",
+ " 0.549 | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 0.429 | \n",
+ " 0.633 | \n",
+ " 0.723 | \n",
+ " 0.725 | \n",
+ " 0.683 | \n",
+ " 0.989 | \n",
+ " 0.985 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 0.535 | \n",
+ " 0.474 | \n",
+ " 0.645 | \n",
+ " 0.633 | \n",
+ " 0.696 | \n",
+ " 0.472 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 0.569 | \n",
+ " 0.599 | \n",
+ " 0.578 | \n",
+ " 0.656 | \n",
+ " 0.495 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 0.520 | \n",
+ " 0.530 | \n",
+ " 0.531 | \n",
+ " 0.332 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 0.358 | \n",
+ " 0.422 | \n",
+ " 0.299 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 0.350 | \n",
+ " 0.315 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 0.523 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "Averages of the Ratio of Incremental Paid Claims to Previous Case Outstanding:\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
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+ " | | \n",
+ " 24 | \n",
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+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | Latest 5 | \n",
+ " 0.464 | \n",
+ " 0.468 | \n",
+ " 0.555 | \n",
+ " 0.602 | \n",
+ " 0.731 | \n",
+ " 0.751 | \n",
+ " 0.730 | \n",
+ " 0.565 | \n",
+ " 0.501 | \n",
+ " 0.817 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | Latest 2 | \n",
+ " 0.437 | \n",
+ " 0.369 | \n",
+ " 0.415 | \n",
+ " 0.494 | \n",
+ " 0.596 | \n",
+ " 0.730 | \n",
+ " 0.852 | \n",
+ " 0.618 | \n",
+ " 0.501 | \n",
+ " 0.817 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | Latest 5x1 | \n",
+ " 0.467 | \n",
+ " 0.475 | \n",
+ " 0.585 | \n",
+ " 0.651 | \n",
+ " 0.754 | \n",
+ " 0.765 | \n",
+ " 0.767 | \n",
+ " 0.549 | \n",
+ " 0.501 | \n",
+ " 0.817 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "Selected Ratio of Incremental Paid Claims to Previous Case Outstanding:\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | Selected | \n",
+ " 0.437 | \n",
+ " 0.369 | \n",
+ " 0.415 | \n",
+ " 0.494 | \n",
+ " 0.596 | \n",
+ " 0.730 | \n",
+ " 0.852 | \n",
+ " 0.618 | \n",
+ " 0.501 | \n",
+ " 0.817 | \n",
+ " 1.100 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "dev_cols_e2 = [24, 36, 48, 60, 72, 84, 96, 108, 120, 132]\n",
+ "\n",
+ "# Compute unrounded ratios\n",
+ "xyz_ratio_paid_to_case = pd.DataFrame(index=xyz_case_df.index)\n",
+ "for d in dev_cols_e2:\n",
+ " xyz_ratio_paid_to_case[d] = xyz_incr_paid_df[d] / xyz_case_df[d - 12]\n",
+ "\n",
+ "# Unrounded averages\n",
+ "xyz_latest_5_paid = xyz_ratio_paid_to_case.apply(lambda s: s.dropna().tail(5).mean())\n",
+ "xyz_latest_2_paid = xyz_ratio_paid_to_case.apply(lambda s: s.dropna().tail(2).mean())\n",
+ "xyz_medial_5x1_paid = xyz_ratio_paid_to_case.apply(calc_medial_5x1)\n",
+ "\n",
+ "xyz_averages_paid_df = pd.DataFrame({\n",
+ " \"Latest 5\": xyz_latest_5_paid,\n",
+ " \"Latest 2\": xyz_latest_2_paid,\n",
+ " \"Latest 5x1\": xyz_medial_5x1_paid,\n",
+ "}).T\n",
+ "xyz_averages_paid_df[\"To Ult\"] = np.nan\n",
+ "\n",
+ "# Selected: Latest 2 average, tail to ultimate = 1.100\n",
+ "xyz_selected_paid = xyz_latest_2_paid.copy()\n",
+ "xyz_selected_paid[\"To Ult\"] = 1.100\n",
+ "xyz_selected_paid_df = pd.DataFrame([xyz_selected_paid], index=[\"Selected\"])\n",
+ "\n",
+ "print(\"Ratio of Incremental Paid Claims to Previous Case Outstanding:\")\n",
+ "nb_display(xyz_ratio_paid_to_case.style.format(\"{:.3f}\", na_rep=\"\"))\n",
+ "\n",
+ "print(\n",
+ " \"\\nAverages of the Ratio of Incremental Paid Claims to Previous Case Outstanding:\"\n",
+ ")\n",
+ "nb_display(xyz_averages_paid_df.style.format(\"{:.3f}\", na_rep=\"\"))\n",
+ "\n",
+ "print(\"\\nSelected Ratio of Incremental Paid Claims to Previous Case Outstanding:\")\n",
+ "nb_display(xyz_selected_paid_df.style.format(\"{:.3f}\", na_rep=\"\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_19",
+ "metadata": {},
+ "source": [
+ "## Exhibit II Sheet 3\n",
+ "\n",
+ "### Ratio of Case Outstanding to Previous Case Outstanding\n",
+ "\n",
+ "Calculates the runoff of case reserves:\n",
+ "$$\\text{Ratio}_{d} = \\frac{\\text{Case Outstanding}_{d}}{\\text{Case Outstanding}_{d-12}}$$\n",
+ "\n",
+ "- **Latest 2 Average**: Captures recent case reserve adequacy strengthening.\n",
+ "- **Selected**: Matches the **Latest 2** average, with maturity 132 and **To Ult = 0.000**.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 9,
+ "id": "cell_code_20",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:36.939184Z",
+ "iopub.status.busy": "2026-09-28T14:20:36.938572Z",
+ "iopub.status.idle": "2026-09-28T14:20:36.980230Z",
+ "shell.execute_reply": "2026-09-28T14:20:36.979401Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Ratio of Case Outstanding to Previous Case Outstanding:\n"
+ ]
+ },
+ {
+ "data": {
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+ "\n",
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+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " | \n",
+ " | \n",
+ " 0.794 | \n",
+ " 0.812 | \n",
+ " 0.781 | \n",
+ " 0.591 | \n",
+ " 1.346 | \n",
+ " 0.438 | \n",
+ " 0.083 | \n",
+ " 0.000 | \n",
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+ " \n",
+ " | 1999 | \n",
+ " | \n",
+ " 0.762 | \n",
+ " 0.866 | \n",
+ " 0.767 | \n",
+ " 0.399 | \n",
+ " 0.914 | \n",
+ " 0.410 | \n",
+ " 0.738 | \n",
+ " 0.605 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 0.851 | \n",
+ " 0.798 | \n",
+ " 0.954 | \n",
+ " 0.586 | \n",
+ " 1.027 | \n",
+ " 0.665 | \n",
+ " 0.430 | \n",
+ " 0.289 | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 0.977 | \n",
+ " 0.866 | \n",
+ " 0.916 | \n",
+ " 1.232 | \n",
+ " 0.616 | \n",
+ " 0.243 | \n",
+ " 0.190 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 1.185 | \n",
+ " 1.032 | \n",
+ " 1.213 | \n",
+ " 0.801 | \n",
+ " 0.647 | \n",
+ " 0.462 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 1.360 | \n",
+ " 1.643 | \n",
+ " 1.002 | \n",
+ " 0.549 | \n",
+ " 0.520 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 2.050 | \n",
+ " 1.087 | \n",
+ " 0.859 | \n",
+ " 0.618 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 1.374 | \n",
+ " 1.229 | \n",
+ " 0.708 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 1.487 | \n",
+ " 0.742 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 1.246 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "Averages of the Ratio of Case Outstanding to Previous Case Outstanding:\n"
+ ]
+ },
+ {
+ "data": {
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+ "\n",
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+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | Latest 5 | \n",
+ " 1.503 | \n",
+ " 1.147 | \n",
+ " 0.939 | \n",
+ " 0.757 | \n",
+ " 0.642 | \n",
+ " 0.575 | \n",
+ " 0.594 | \n",
+ " 0.488 | \n",
+ " 0.344 | \n",
+ " 0.000 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | Latest 2 | \n",
+ " 1.367 | \n",
+ " 0.986 | \n",
+ " 0.783 | \n",
+ " 0.584 | \n",
+ " 0.583 | \n",
+ " 0.353 | \n",
+ " 0.310 | \n",
+ " 0.514 | \n",
+ " 0.344 | \n",
+ " 0.000 | \n",
+ " | \n",
+ "
\n",
+ " \n",
+ " | Latest 5x1 | \n",
+ " 1.407 | \n",
+ " 1.116 | \n",
+ " 0.925 | \n",
+ " 0.668 | \n",
+ " 0.594 | \n",
+ " 0.573 | \n",
+ " 0.420 | \n",
+ " 0.438 | \n",
+ " 0.344 | \n",
+ " 0.000 | \n",
+ " | \n",
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+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "Selected Ratio of Case Outstanding to Previous Case Outstanding:\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | Selected | \n",
+ " 1.367 | \n",
+ " 0.986 | \n",
+ " 0.783 | \n",
+ " 0.584 | \n",
+ " 0.583 | \n",
+ " 0.353 | \n",
+ " 0.310 | \n",
+ " 0.514 | \n",
+ " 0.344 | \n",
+ " 0.000 | \n",
+ " 0.000 | \n",
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+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "xyz_ratio_case_to_case = pd.DataFrame(index=xyz_case_df.index)\n",
+ "for d in dev_cols_e2:\n",
+ " xyz_ratio_case_to_case[d] = xyz_case_df[d] / xyz_case_df[d - 12]\n",
+ "\n",
+ "# Unrounded averages\n",
+ "xyz_latest_5_case = xyz_ratio_case_to_case.apply(lambda s: s.dropna().tail(5).mean())\n",
+ "xyz_latest_2_case = xyz_ratio_case_to_case.apply(lambda s: s.dropna().tail(2).mean())\n",
+ "xyz_medial_5x1_case = xyz_ratio_case_to_case.apply(calc_medial_5x1)\n",
+ "\n",
+ "xyz_averages_case_df = pd.DataFrame({\n",
+ " \"Latest 5\": xyz_latest_5_case,\n",
+ " \"Latest 2\": xyz_latest_2_case,\n",
+ " \"Latest 5x1\": xyz_medial_5x1_case,\n",
+ "}).T\n",
+ "xyz_averages_case_df[\"To Ult\"] = np.nan\n",
+ "\n",
+ "# Selected: Latest 2 average, age 132 and To Ult set to 0.000\n",
+ "xyz_selected_case = xyz_latest_2_case.copy()\n",
+ "xyz_selected_case[132] = 0.000\n",
+ "xyz_selected_case[\"To Ult\"] = 0.000\n",
+ "xyz_selected_case_df = pd.DataFrame([xyz_selected_case], index=[\"Selected\"])\n",
+ "\n",
+ "print(\"Ratio of Case Outstanding to Previous Case Outstanding:\")\n",
+ "nb_display(xyz_ratio_case_to_case.style.format(\"{:.3f}\", na_rep=\"\"))\n",
+ "\n",
+ "print(\"\\nAverages of the Ratio of Case Outstanding to Previous Case Outstanding:\")\n",
+ "nb_display(xyz_averages_case_df.style.format(\"{:.3f}\", na_rep=\"\"))\n",
+ "\n",
+ "print(\"\\nSelected Ratio of Case Outstanding to Previous Case Outstanding:\")\n",
+ "nb_display(xyz_selected_case_df.style.format(\"{:.3f}\", na_rep=\"\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_21",
+ "metadata": {},
+ "source": [
+ "## Exhibit II Sheet 4\n",
+ "\n",
+ "### Projection of Paid Claims ($000)\n",
+ "\n",
+ "Using the selected ratios for XYZ Insurer:\n",
+ "1. Complete square of Case Outstanding through age 132 and `To Ult` (0.0).\n",
+ "2. Complete square of Incremental Paid Claims through age 132 and `To Ult` ($1.100 \\times \\text{Case}_{132}$).\n",
+ "3. Cumulative Paid Claims through `To Ult`.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 10,
+ "id": "cell_code_22",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:36.982891Z",
+ "iopub.status.busy": "2026-09-28T14:20:36.982481Z",
+ "iopub.status.idle": "2026-09-28T14:20:37.082555Z",
+ "shell.execute_reply": "2026-09-28T14:20:37.081803Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "1. Case Outstanding as of (months) ($000) [Projected cells highlighted]:\n"
+ ]
+ },
+ {
+ "data": {
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+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " nan | \n",
+ " nan | \n",
+ " 4,862 | \n",
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+ " nan | \n",
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+ " 14,374 | \n",
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\n",
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+ " 10,288 | \n",
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+ " 6,046 | \n",
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+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 10,493 | \n",
+ " 12,438 | \n",
+ " 12,834 | \n",
+ " 15,572 | \n",
+ " 12,469 | \n",
+ " 8,072 | \n",
+ " 3,732 | \n",
+ " 1,156 | \n",
+ " 594 | \n",
+ " 205 | \n",
+ " 0 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 7,908 | \n",
+ " 10,755 | \n",
+ " 17,671 | \n",
+ " 17,702 | \n",
+ " 9,726 | \n",
+ " 5,053 | \n",
+ " 1,783 | \n",
+ " 552 | \n",
+ " 284 | \n",
+ " 98 | \n",
+ " 0 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 14,774 | \n",
+ " 30,282 | \n",
+ " 32,916 | \n",
+ " 28,268 | \n",
+ " 17,477 | \n",
+ " 10,197 | \n",
+ " 3,598 | \n",
+ " 1,115 | \n",
+ " 573 | \n",
+ " 197 | \n",
+ " 0 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 25,631 | \n",
+ " 35,213 | \n",
+ " 43,267 | \n",
+ " 30,629 | \n",
+ " 17,883 | \n",
+ " 10,434 | \n",
+ " 3,681 | \n",
+ " 1,141 | \n",
+ " 586 | \n",
+ " 202 | \n",
+ " 0 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 23,535 | \n",
+ " 35,005 | \n",
+ " 25,985 | \n",
+ " 20,355 | \n",
+ " 11,884 | \n",
+ " 6,934 | \n",
+ " 2,446 | \n",
+ " 758 | \n",
+ " 389 | \n",
+ " 134 | \n",
+ " 0 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 15,948 | \n",
+ " 19,867 | \n",
+ " 19,579 | \n",
+ " 15,337 | \n",
+ " 8,955 | \n",
+ " 5,225 | \n",
+ " 1,843 | \n",
+ " 571 | \n",
+ " 293 | \n",
+ " 101 | \n",
+ " 0 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " 15,223 | \n",
+ " 20,803 | \n",
+ " 20,502 | \n",
+ " 16,060 | \n",
+ " 9,377 | \n",
+ " 5,471 | \n",
+ " 1,930 | \n",
+ " 598 | \n",
+ " 307 | \n",
+ " 106 | \n",
+ " 0 | \n",
+ " 0 | \n",
+ "
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+ " \n",
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+ ""
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+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "2. Incremental Paid Claims as of (months) ($000) [Projected cells highlighted]:\n"
+ ]
+ },
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+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " nan | \n",
+ " nan | \n",
+ " 6,309 | \n",
+ " 2,212 | \n",
+ " 1,561 | \n",
+ " 1,538 | \n",
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+ " 892 | \n",
+ " 453 | \n",
+ " 58 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " nan | \n",
+ " 4,666 | \n",
+ " 5,195 | \n",
+ " 4,110 | \n",
+ " 4,156 | \n",
+ " 3,905 | \n",
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+ " 635 | \n",
+ " 446 | \n",
+ " 225 | \n",
+ " 237 | \n",
+ " 0 | \n",
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+ " \n",
+ " | 2000 | \n",
+ " 1,302 | \n",
+ " 5,211 | \n",
+ " 5,626 | \n",
+ " 5,689 | \n",
+ " 6,202 | \n",
+ " 4,823 | \n",
+ " 4,369 | \n",
+ " 2,680 | \n",
+ " 880 | \n",
+ " 232 | \n",
+ " 131 | \n",
+ " 0 | \n",
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\n",
+ " \n",
+ " | 2001 | \n",
+ " 1,539 | \n",
+ " 4,413 | \n",
+ " 6,367 | \n",
+ " 6,290 | \n",
+ " 5,778 | \n",
+ " 6,703 | \n",
+ " 5,980 | \n",
+ " 1,449 | \n",
+ " 172 | \n",
+ " 72 | \n",
+ " 40 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 2,318 | \n",
+ " 5,614 | \n",
+ " 5,890 | \n",
+ " 8,273 | \n",
+ " 9,850 | \n",
+ " 8,684 | \n",
+ " 3,808 | \n",
+ " 3,180 | \n",
+ " 715 | \n",
+ " 298 | \n",
+ " 167 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 1,743 | \n",
+ " 4,497 | \n",
+ " 6,443 | \n",
+ " 10,209 | \n",
+ " 11,613 | \n",
+ " 4,815 | \n",
+ " 3,691 | \n",
+ " 1,519 | \n",
+ " 341 | \n",
+ " 142 | \n",
+ " 80 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 2,221 | \n",
+ " 7,677 | \n",
+ " 16,052 | \n",
+ " 17,489 | \n",
+ " 9,372 | \n",
+ " 10,412 | \n",
+ " 7,448 | \n",
+ " 3,065 | \n",
+ " 689 | \n",
+ " 287 | \n",
+ " 161 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 3,043 | \n",
+ " 9,176 | \n",
+ " 14,854 | \n",
+ " 12,953 | \n",
+ " 15,124 | \n",
+ " 10,654 | \n",
+ " 7,621 | \n",
+ " 3,137 | \n",
+ " 705 | \n",
+ " 293 | \n",
+ " 165 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 3,531 | \n",
+ " 8,247 | \n",
+ " 11,041 | \n",
+ " 10,793 | \n",
+ " 10,051 | \n",
+ " 7,080 | \n",
+ " 5,065 | \n",
+ " 2,085 | \n",
+ " 469 | \n",
+ " 195 | \n",
+ " 110 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 3,529 | \n",
+ " 8,336 | \n",
+ " 7,323 | \n",
+ " 8,132 | \n",
+ " 7,573 | \n",
+ " 5,335 | \n",
+ " 3,816 | \n",
+ " 1,571 | \n",
+ " 353 | \n",
+ " 147 | \n",
+ " 83 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " 3,409 | \n",
+ " 6,646 | \n",
+ " 7,668 | \n",
+ " 8,515 | \n",
+ " 7,930 | \n",
+ " 5,586 | \n",
+ " 3,996 | \n",
+ " 1,645 | \n",
+ " 370 | \n",
+ " 154 | \n",
+ " 86 | \n",
+ " 0 | \n",
+ "
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+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ },
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "\n",
+ "3. Cumulative Paid Claims as of (months) ($000):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " 12 | \n",
+ " 24 | \n",
+ " 36 | \n",
+ " 48 | \n",
+ " 60 | \n",
+ " 72 | \n",
+ " 84 | \n",
+ " 96 | \n",
+ " 108 | \n",
+ " 120 | \n",
+ " 132 | \n",
+ " To Ult | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " nan | \n",
+ " nan | \n",
+ " 6,309 | \n",
+ " 8,521 | \n",
+ " 10,082 | \n",
+ " 11,620 | \n",
+ " 13,242 | \n",
+ " 14,419 | \n",
+ " 15,311 | \n",
+ " 15,764 | \n",
+ " 15,822 | \n",
+ " 15,822 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " nan | \n",
+ " 4,666 | \n",
+ " 9,861 | \n",
+ " 13,971 | \n",
+ " 18,127 | \n",
+ " 22,032 | \n",
+ " 23,511 | \n",
+ " 24,146 | \n",
+ " 24,592 | \n",
+ " 24,817 | \n",
+ " 25,054 | \n",
+ " 25,054 | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 1,302 | \n",
+ " 6,513 | \n",
+ " 12,139 | \n",
+ " 17,828 | \n",
+ " 24,030 | \n",
+ " 28,853 | \n",
+ " 33,222 | \n",
+ " 35,902 | \n",
+ " 36,782 | \n",
+ " 37,014 | \n",
+ " 37,145 | \n",
+ " 37,145 | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 1,539 | \n",
+ " 5,952 | \n",
+ " 12,319 | \n",
+ " 18,609 | \n",
+ " 24,387 | \n",
+ " 31,090 | \n",
+ " 37,070 | \n",
+ " 38,519 | \n",
+ " 38,691 | \n",
+ " 38,763 | \n",
+ " 38,804 | \n",
+ " 38,804 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 2,318 | \n",
+ " 7,932 | \n",
+ " 13,822 | \n",
+ " 22,095 | \n",
+ " 31,945 | \n",
+ " 40,629 | \n",
+ " 44,437 | \n",
+ " 47,617 | \n",
+ " 48,332 | \n",
+ " 48,629 | \n",
+ " 48,796 | \n",
+ " 48,796 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 1,743 | \n",
+ " 6,240 | \n",
+ " 12,683 | \n",
+ " 22,892 | \n",
+ " 34,505 | \n",
+ " 39,320 | \n",
+ " 43,011 | \n",
+ " 44,530 | \n",
+ " 44,871 | \n",
+ " 45,013 | \n",
+ " 45,093 | \n",
+ " 45,093 | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 2,221 | \n",
+ " 9,898 | \n",
+ " 25,950 | \n",
+ " 43,439 | \n",
+ " 52,811 | \n",
+ " 63,223 | \n",
+ " 70,671 | \n",
+ " 73,737 | \n",
+ " 74,426 | \n",
+ " 74,712 | \n",
+ " 74,874 | \n",
+ " 74,874 | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 3,043 | \n",
+ " 12,219 | \n",
+ " 27,073 | \n",
+ " 40,026 | \n",
+ " 55,150 | \n",
+ " 65,804 | \n",
+ " 73,425 | \n",
+ " 76,561 | \n",
+ " 77,266 | \n",
+ " 77,560 | \n",
+ " 77,725 | \n",
+ " 77,725 | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 3,531 | \n",
+ " 11,778 | \n",
+ " 22,819 | \n",
+ " 33,612 | \n",
+ " 43,663 | \n",
+ " 50,743 | \n",
+ " 55,808 | \n",
+ " 57,892 | \n",
+ " 58,361 | \n",
+ " 58,556 | \n",
+ " 58,666 | \n",
+ " 58,666 | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 3,529 | \n",
+ " 11,865 | \n",
+ " 19,188 | \n",
+ " 27,321 | \n",
+ " 34,894 | \n",
+ " 40,229 | \n",
+ " 44,045 | \n",
+ " 45,616 | \n",
+ " 45,969 | \n",
+ " 46,116 | \n",
+ " 46,198 | \n",
+ " 46,198 | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " 3,409 | \n",
+ " 10,055 | \n",
+ " 17,723 | \n",
+ " 26,239 | \n",
+ " 34,169 | \n",
+ " 39,755 | \n",
+ " 43,751 | \n",
+ " 45,395 | \n",
+ " 45,765 | \n",
+ " 45,919 | \n",
+ " 46,005 | \n",
+ " 46,005 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "# 1. Complete Case Outstanding Square\n",
+ "xyz_completed_case_df = xyz_case_df.copy()\n",
+ "xyz_completed_case_df[\"To Ult\"] = 0.0\n",
+ "xyz_is_projected_case = pd.DataFrame(\n",
+ " False, index=xyz_completed_case_df.index, columns=xyz_completed_case_df.columns\n",
+ ")\n",
+ "\n",
+ "for ay in xyz_completed_case_df.index:\n",
+ " for d in dev_cols_e2:\n",
+ " if pd.isna(xyz_completed_case_df.loc[ay, d]):\n",
+ " prev_case = xyz_completed_case_df.loc[ay, d - 12]\n",
+ " xyz_completed_case_df.loc[ay, d] = prev_case * xyz_selected_case[d]\n",
+ " xyz_is_projected_case.loc[ay, d] = True\n",
+ " xyz_completed_case_df.loc[ay, \"To Ult\"] = 0.0\n",
+ " xyz_is_projected_case.loc[ay, \"To Ult\"] = True\n",
+ "\n",
+ "# 2. Complete Incremental Paid Square\n",
+ "xyz_completed_incr_paid_df = xyz_incr_paid_df.copy()\n",
+ "xyz_completed_incr_paid_df[\"To Ult\"] = np.nan\n",
+ "xyz_is_projected_paid = pd.DataFrame(\n",
+ " False,\n",
+ " index=xyz_completed_incr_paid_df.index,\n",
+ " columns=xyz_completed_incr_paid_df.columns,\n",
+ ")\n",
+ "\n",
+ "for ay in xyz_completed_incr_paid_df.index:\n",
+ " for d in dev_cols_e2:\n",
+ " if pd.isna(xyz_completed_incr_paid_df.loc[ay, d]):\n",
+ " prev_case = xyz_completed_case_df.loc[ay, d - 12]\n",
+ " xyz_completed_incr_paid_df.loc[ay, d] = prev_case * xyz_selected_paid[d]\n",
+ " xyz_is_projected_paid.loc[ay, d] = True\n",
+ " case_132 = xyz_completed_case_df.loc[ay, 132]\n",
+ " xyz_completed_incr_paid_df.loc[ay, \"To Ult\"] = (\n",
+ " case_132 * xyz_selected_paid[\"To Ult\"]\n",
+ " )\n",
+ " xyz_is_projected_paid.loc[ay, \"To Ult\"] = True\n",
+ "\n",
+ "# 3. Cumulative Paid Claims through To Ult\n",
+ "xyz_completed_cum_paid_df = xyz_completed_incr_paid_df.cumsum(axis=1)\n",
+ "\n",
+ "print(\"1. Case Outstanding as of (months) ($000) [Projected cells highlighted]:\")\n",
+ "nb_display(style_projected(xyz_completed_case_df, xyz_is_projected_case))\n",
+ "\n",
+ "print(\n",
+ " \"\\n2. Incremental Paid Claims as of (months) ($000) [Projected cells highlighted]:\"\n",
+ ")\n",
+ "nb_display(style_projected(xyz_completed_incr_paid_df, xyz_is_projected_paid))\n",
+ "\n",
+ "print(\"\\n3. Cumulative Paid Claims as of (months) ($000):\")\n",
+ "nb_display(xyz_completed_cum_paid_df.style.format(\"{:,.0f}\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_23",
+ "metadata": {},
+ "source": [
+ "## Exhibit II Sheet 5\n",
+ "\n",
+ "### Development of Unpaid Claim Estimate ($000)\n",
+ "\n",
+ "Reconciles the unpaid claim estimate for XYZ Insurer using the `format_exh` styler:\n",
+ "- **(2) Reported Claims**: Latest diagonal of reported claims.\n",
+ "- **(3) Paid Claims**: Latest diagonal of cumulative paid claims.\n",
+ "- **(4) Projected Ultimate**: Cumulative paid claims through `To Ult`.\n",
+ "- **(5) Case Outstanding**: $(2) - (3)$.\n",
+ "- **(6) Estimated IBNR**: $(4) - (2)$.\n",
+ "- **(7) Total Unpaid**: $(4) - (3)$.\n",
+ "\n",
+ "> [!NOTE]\n",
+ "> **Textbook Inconsistency Note (Accident Year 2000 at Age 120)**:\n",
+ "> In Friedland's printed Exhibit II Sheet 4 (p. 278) and Sheet 5, row 2000 at development age 120 displays incremental paid claims of 0 instead of the continuous projection $\\$465 \\\\times 0.501 = \\\\$233$.\n",
+ "> Continuous mathematical application yields $\\$37,145$ for AY 2000 and a total ultimate of $\\$514,181$, whereas the printed table shows $\\$36,912$ and $\\$513,944$ respectively.\n",
+ "> The underlying cause is a spreadsheet formula omission in the author's template.\n",
+ "> The overall impact on the total ultimate estimate is $\\$237$ (0.046%).\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 11,
+ "id": "cell_code_24",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:37.087082Z",
+ "iopub.status.busy": "2026-09-28T14:20:37.086390Z",
+ "iopub.status.idle": "2026-09-28T14:20:37.143204Z",
+ "shell.execute_reply": "2026-09-28T14:20:37.142203Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Development of Unpaid Claim Estimate ($000):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | Accident Year | \n",
+ " Reported Claims | \n",
+ " Paid Claims | \n",
+ " Projected Ultimate | \n",
+ " Case Outstanding | \n",
+ " Estimated IBNR | \n",
+ " Total Unpaid | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | (1) | \n",
+ " (2) | \n",
+ " (3) | \n",
+ " (4) | \n",
+ " (5) | \n",
+ " (6) | \n",
+ " (7) | \n",
+ "
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+ "
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+ " \n",
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+ " \n",
+ " \n",
+ " \n",
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+ " \n",
+ " \n",
+ "
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+ " \n",
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+ " \n",
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+ "
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+ "
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+ " \n",
+ " \n",
+ " \n",
+ " \n",
+ " \n",
+ " \n",
+ " \n",
+ " \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "xyz_sheet5_df = pd.DataFrame(index=xyz_case_df.index)\n",
+ "xyz_sheet5_df[\"Reported Claims\"] = (\n",
+ " xyz_rep.latest_diagonal.to_frame(origin_as_datetime=False).iloc[:, 0].values\n",
+ ")\n",
+ "xyz_sheet5_df[\"Paid Claims\"] = (\n",
+ " xyz_paid.latest_diagonal.to_frame(origin_as_datetime=False).iloc[:, 0].values\n",
+ ")\n",
+ "xyz_sheet5_df[\"Projected Ultimate\"] = xyz_completed_cum_paid_df[\"To Ult\"].values\n",
+ "xyz_sheet5_df[\"Case Outstanding\"] = (\n",
+ " xyz_sheet5_df[\"Reported Claims\"] - xyz_sheet5_df[\"Paid Claims\"]\n",
+ ")\n",
+ "xyz_sheet5_df[\"Estimated IBNR\"] = (\n",
+ " xyz_sheet5_df[\"Projected Ultimate\"] - xyz_sheet5_df[\"Reported Claims\"]\n",
+ ")\n",
+ "xyz_sheet5_df[\"Total Unpaid\"] = (\n",
+ " xyz_sheet5_df[\"Projected Ultimate\"] - xyz_sheet5_df[\"Paid Claims\"]\n",
+ ")\n",
+ "xyz_sheet5_df.index = pd.to_datetime(xyz_sheet5_df.index.astype(str) + \"-12-31\")\n",
+ "\n",
+ "print(\"Development of Unpaid Claim Estimate ($000):\")\n",
+ "nb_display(\n",
+ " format_exh(\n",
+ " xyz_sheet5_df,\n",
+ " value_cols=list(xyz_sheet5_df.columns),\n",
+ " total_cols=list(xyz_sheet5_df.columns),\n",
+ " origin_name=\"Accident Year\",\n",
+ " origin_format=\"{:%Y}\",\n",
+ " )\n",
+ ")"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_25",
+ "metadata": {},
+ "source": [
+ "## Exhibit II Sheet 6\n",
+ "\n",
+ "### Summary of Ultimate Claims ($000)\n",
+ "\n",
+ "Comparison of Projected Ultimate Claims across methods:\n",
+ "- **(4) & (5) Dev Method (Reported / Paid)**: Developed in Chapter 7, Exhibit II, Sheet 3.\n",
+ "- **(6) Expected Claims**: Developed in Chapter 8, Exhibit III, Sheet 1.\n",
+ "- **(7) Bornhuetter-Ferguson (Reported)**: Developed in Chapter 9, Exhibit II, Sheet 2.\n",
+ "- **(8) Bornhuetter-Ferguson (Paid)**: Developed in Chapter 9, Exhibit II, Sheet 1.\n",
+ "- **(9) Cape Cod (Reported)**: Developed in Chapter 10, Exhibit II, Sheet 2.\n",
+ "- **(10) Cape Cod (Paid)**: Developed in Chapter 10, Exhibit II, Sheet 1.\n",
+ "- **(11) & (12) Frequency-Severity (Approaches 1 & 2)**: Developed in Chapter 11, Exhibits II & IV.\n",
+ "- **(13) Case Outstanding Dev (Approach 1)**: Developed in Sheet 5 above.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 12,
+ "id": "cell_code_26",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:37.146454Z",
+ "iopub.status.busy": "2026-09-28T14:20:37.145829Z",
+ "iopub.status.idle": "2026-09-28T14:20:37.161871Z",
+ "shell.execute_reply": "2026-09-28T14:20:37.161061Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Summary of Ultimate Claims ($000):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " Dev Method (Reported) (4) | \n",
+ " Dev Method (Paid) (5) | \n",
+ " Expected Claims (6) | \n",
+ " BF (Reported) (7) | \n",
+ " BF (Paid) (8) | \n",
+ " Cape Cod (Reported) (9) | \n",
+ " Cape Cod (Paid) (10) | \n",
+ " Freq-Sev Approach 1 (11) | \n",
+ " Freq-Sev Approach 2 (12) | \n",
+ " Case O/S Dev (13) | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " 16,824 | \n",
+ " 16,824 | \n",
+ " 16,824 | \n",
+ " 16,824 | \n",
+ " 16,824 | \n",
+ " 16,824 | \n",
+ " 16,824 | \n",
+ " 16,824 | \n",
+ " 16,824 | \n",
+ " 15,822 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " 21,876 | \n",
+ " 21,876 | \n",
+ " 21,876 | \n",
+ " 21,876 | \n",
+ " 21,876 | \n",
+ " 21,876 | \n",
+ " 21,876 | \n",
+ " 21,876 | \n",
+ " 21,876 | \n",
+ " 25,054 | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 26,978 | \n",
+ " 26,978 | \n",
+ " 26,978 | \n",
+ " 26,978 | \n",
+ " 26,978 | \n",
+ " 26,978 | \n",
+ " 26,978 | \n",
+ " 26,978 | \n",
+ " 26,978 | \n",
+ " 37,145 | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 30,725 | \n",
+ " 30,725 | \n",
+ " 30,725 | \n",
+ " 30,725 | \n",
+ " 30,725 | \n",
+ " 30,725 | \n",
+ " 30,725 | \n",
+ " 30,725 | \n",
+ " 30,725 | \n",
+ " 38,804 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 36,247 | \n",
+ " 36,247 | \n",
+ " 36,247 | \n",
+ " 36,247 | \n",
+ " 36,247 | \n",
+ " 36,247 | \n",
+ " 36,247 | \n",
+ " 36,247 | \n",
+ " 36,247 | \n",
+ " 48,796 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 43,764 | \n",
+ " 42,522 | \n",
+ " 43,534 | \n",
+ " 43,764 | \n",
+ " 43,105 | \n",
+ " 43,764 | \n",
+ " 43,075 | \n",
+ " 43,764 | \n",
+ " 43,764 | \n",
+ " 45,093 | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " 48,312 | \n",
+ " 46,114 | \n",
+ " 47,713 | \n",
+ " 48,259 | \n",
+ " 47,040 | \n",
+ " 48,261 | \n",
+ " 46,995 | \n",
+ " 47,672 | \n",
+ " 47,447 | \n",
+ " 74,874 | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " 45,155 | \n",
+ " 43,444 | \n",
+ " 44,026 | \n",
+ " 45,057 | \n",
+ " 43,813 | \n",
+ " 45,063 | \n",
+ " 43,743 | \n",
+ " 44,589 | \n",
+ " 45,391 | \n",
+ " 77,725 | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " 43,906 | \n",
+ " 42,125 | \n",
+ " 46,765 | \n",
+ " 44,299 | \n",
+ " 44,211 | \n",
+ " 44,327 | \n",
+ " 44,078 | \n",
+ " 43,905 | \n",
+ " 46,144 | \n",
+ " 58,666 | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 42,964 | \n",
+ " 41,042 | \n",
+ " 46,682 | \n",
+ " 44,018 | \n",
+ " 43,632 | \n",
+ " 44,093 | \n",
+ " 43,376 | \n",
+ " 44,435 | \n",
+ " 46,274 | \n",
+ " 46,198 | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " 41,249 | \n",
+ " 39,686 | \n",
+ " 47,708 | \n",
+ " 44,320 | \n",
+ " 44,081 | \n",
+ " 44,520 | \n",
+ " 43,575 | \n",
+ " 44,062 | \n",
+ " 45,781 | \n",
+ " 46,005 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "# Benchmark Ultimates from prior chapters\n",
+ "prior_ultimates = {\n",
+ " \"Dev Method (Reported) (4)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 43764,\n",
+ " 48312,\n",
+ " 45155,\n",
+ " 43906,\n",
+ " 42964,\n",
+ " 41249,\n",
+ " ],\n",
+ " \"Dev Method (Paid) (5)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 42522,\n",
+ " 46114,\n",
+ " 43444,\n",
+ " 42125,\n",
+ " 41042,\n",
+ " 39686,\n",
+ " ],\n",
+ " \"Expected Claims (6)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 43534,\n",
+ " 47713,\n",
+ " 44026,\n",
+ " 46765,\n",
+ " 46682,\n",
+ " 47708,\n",
+ " ],\n",
+ " \"BF (Reported) (7)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 43764,\n",
+ " 48259,\n",
+ " 45057,\n",
+ " 44299,\n",
+ " 44018,\n",
+ " 44320,\n",
+ " ],\n",
+ " \"BF (Paid) (8)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 43105,\n",
+ " 47040,\n",
+ " 43813,\n",
+ " 44211,\n",
+ " 43632,\n",
+ " 44081,\n",
+ " ],\n",
+ " \"Cape Cod (Reported) (9)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 43764,\n",
+ " 48261,\n",
+ " 45063,\n",
+ " 44327,\n",
+ " 44093,\n",
+ " 44520,\n",
+ " ],\n",
+ " \"Cape Cod (Paid) (10)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 43075,\n",
+ " 46995,\n",
+ " 43743,\n",
+ " 44078,\n",
+ " 43376,\n",
+ " 43575,\n",
+ " ],\n",
+ " \"Freq-Sev Approach 1 (11)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 43764,\n",
+ " 47672,\n",
+ " 44589,\n",
+ " 43905,\n",
+ " 44435,\n",
+ " 44062,\n",
+ " ],\n",
+ " \"Freq-Sev Approach 2 (12)\": [\n",
+ " 16824,\n",
+ " 21876,\n",
+ " 26978,\n",
+ " 30725,\n",
+ " 36247,\n",
+ " 43764,\n",
+ " 47447,\n",
+ " 45391,\n",
+ " 46144,\n",
+ " 46274,\n",
+ " 45781,\n",
+ " ],\n",
+ "}\n",
+ "\n",
+ "summary_ult_df = pd.DataFrame(prior_ultimates, index=xyz_case_df.index)\n",
+ "summary_ult_df[\"Case O/S Dev (13)\"] = xyz_sheet5_df[\"Projected Ultimate\"].values\n",
+ "\n",
+ "# Display summary table with integer formatting\n",
+ "print(\"Summary of Ultimate Claims ($000):\")\n",
+ "nb_display(summary_ult_df.style.format(\"{:,.0f}\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_27",
+ "metadata": {},
+ "source": [
+ "## Exhibit II Sheet 7\n",
+ "\n",
+ "### Summary of Estimated IBNR ($000)\n",
+ "\n",
+ "Estimated IBNR across methods: $\\text{IBNR} = \\text{Projected Ultimate} - \\text{Reported Claims}$.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 13,
+ "id": "cell_code_28",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:37.164778Z",
+ "iopub.status.busy": "2026-09-28T14:20:37.164407Z",
+ "iopub.status.idle": "2026-09-28T14:20:37.190513Z",
+ "shell.execute_reply": "2026-09-28T14:20:37.189481Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Summary of Estimated IBNR ($000):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " Dev Method (Reported) (4) | \n",
+ " Dev Method (Paid) (5) | \n",
+ " Expected Claims (6) | \n",
+ " BF (Reported) (7) | \n",
+ " BF (Paid) (8) | \n",
+ " Cape Cod (Reported) (9) | \n",
+ " Cape Cod (Paid) (10) | \n",
+ " Freq-Sev Approach 1 (11) | \n",
+ " Freq-Sev Approach 2 (12) | \n",
+ " Case O/S Dev (13) | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " 1,002 | \n",
+ " 1,002 | \n",
+ " 1,002 | \n",
+ " 1,002 | \n",
+ " 1,002 | \n",
+ " 1,002 | \n",
+ " 1,002 | \n",
+ " 1,002 | \n",
+ " 1,002 | \n",
+ " 0 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " -3,231 | \n",
+ " -3,231 | \n",
+ " -3,231 | \n",
+ " -3,231 | \n",
+ " -3,231 | \n",
+ " -3,231 | \n",
+ " -3,231 | \n",
+ " -3,231 | \n",
+ " -3,231 | \n",
+ " -53 | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " -10,268 | \n",
+ " -10,268 | \n",
+ " -10,268 | \n",
+ " -10,268 | \n",
+ " -10,268 | \n",
+ " -10,268 | \n",
+ " -10,268 | \n",
+ " -10,268 | \n",
+ " -10,268 | \n",
+ " -101 | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " -8,073 | \n",
+ " -8,073 | \n",
+ " -8,073 | \n",
+ " -8,073 | \n",
+ " -8,073 | \n",
+ " -8,073 | \n",
+ " -8,073 | \n",
+ " -8,073 | \n",
+ " -8,073 | \n",
+ " 6 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " -11,922 | \n",
+ " -11,922 | \n",
+ " -11,922 | \n",
+ " -11,922 | \n",
+ " -11,922 | \n",
+ " -11,922 | \n",
+ " -11,922 | \n",
+ " -11,922 | \n",
+ " -11,922 | \n",
+ " 627 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " -609 | \n",
+ " -1,851 | \n",
+ " -839 | \n",
+ " -609 | \n",
+ " -1,268 | \n",
+ " -609 | \n",
+ " -1,298 | \n",
+ " -609 | \n",
+ " -609 | \n",
+ " 720 | \n",
+ "
\n",
+ " \n",
+ " | 2004 | \n",
+ " -21,976 | \n",
+ " -24,174 | \n",
+ " -22,575 | \n",
+ " -22,029 | \n",
+ " -23,248 | \n",
+ " -22,027 | \n",
+ " -23,293 | \n",
+ " -22,616 | \n",
+ " -22,841 | \n",
+ " 4,586 | \n",
+ "
\n",
+ " \n",
+ " | 2005 | \n",
+ " -25,500 | \n",
+ " -27,211 | \n",
+ " -26,629 | \n",
+ " -25,598 | \n",
+ " -26,842 | \n",
+ " -25,592 | \n",
+ " -26,912 | \n",
+ " -26,066 | \n",
+ " -25,264 | \n",
+ " 7,070 | \n",
+ "
\n",
+ " \n",
+ " | 2006 | \n",
+ " -4,898 | \n",
+ " -6,679 | \n",
+ " -2,039 | \n",
+ " -4,505 | \n",
+ " -4,593 | \n",
+ " -4,477 | \n",
+ " -4,726 | \n",
+ " -4,899 | \n",
+ " -2,660 | \n",
+ " 9,862 | \n",
+ "
\n",
+ " \n",
+ " | 2007 | \n",
+ " 11,232 | \n",
+ " 9,310 | \n",
+ " 14,950 | \n",
+ " 12,286 | \n",
+ " 11,900 | \n",
+ " 12,361 | \n",
+ " 11,644 | \n",
+ " 12,703 | \n",
+ " 14,542 | \n",
+ " 14,466 | \n",
+ "
\n",
+ " \n",
+ " | 2008 | \n",
+ " 22,617 | \n",
+ " 21,054 | \n",
+ " 29,076 | \n",
+ " 25,688 | \n",
+ " 25,449 | \n",
+ " 25,888 | \n",
+ " 24,943 | \n",
+ " 25,430 | \n",
+ " 27,149 | \n",
+ " 27,373 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "summary_ibnr_df = pd.DataFrame(index=xyz_case_df.index)\n",
+ "rep_diag = xyz_rep.latest_diagonal.to_frame(origin_as_datetime=False).iloc[:, 0].values\n",
+ "\n",
+ "for col in summary_ult_df.columns:\n",
+ " summary_ibnr_df[col] = summary_ult_df[col] - rep_diag\n",
+ "\n",
+ "print(\"Summary of Estimated IBNR ($000):\")\n",
+ "nb_display(summary_ibnr_df.style.format(\"{:,.0f}\"))"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_29",
+ "metadata": {},
+ "source": [
+ "---\n",
+ "\n",
+ "## Exhibit III Analysis\n",
+ "\n",
+ "In Exhibit III, Friedland demonstrates **Approach #2 (Implied Case Development Factors)** for self-insurers or lines where historical case runoff triangles are unavailable, using benchmark reported and paid claim development patterns.\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_30",
+ "metadata": {},
+ "source": [
+ "## Exhibit III Sheet 1\n",
+ "\n",
+ "### Self-Insurer Case Outstanding Only ($)\n",
+ "\n",
+ "Approach #2 derives case outstanding development factors to ultimate from industry benchmark reported and paid claim development patterns.\n",
+ "\n",
+ "#### Actuarial Formulation (Friedland p. 235)\n",
+ "Let $f_{\\text{rep}}(d)$ and $f_{\\text{paid}}(d)$ be the cumulative development factors to ultimate from maturity $d$.\n",
+ "The percentage of ultimate claims reported and paid at maturity $d$ are:\n",
+ "$$\\%\\text{Reported}(d) = \\frac{1}{f_{\\text{rep}}(d)}, \\quad \\%\\text{Paid}(d) = \\frac{1}{f_{\\text{paid}}(d)}$$\n",
+ "\n",
+ "The proportion of ultimate claims remaining in case outstanding is:\n",
+ "$$\\%\\text{Case}(d) = \\%\\text{Reported}(d) - \\%\\text{Paid}(d) = \\frac{1}{f_{\\text{rep}}(d)} - \\frac{1}{f_{\\text{paid}}(d)}$$\n",
+ "\n",
+ "Since unpaid claims equal $1 - \\%\\text{Paid}(d)$, the ratio of unpaid claims to case outstanding (the **Case Outstanding CDF**) is:\n",
+ "$$\\text{Case CDF}(d) = \\frac{1 - \\%\\text{Paid}(d)}{\\%\\text{Case}(d)} = \\frac{1 - \\frac{1}{f_{\\text{paid}}(d)}}{\\frac{1}{f_{\\text{rep}}(d)} - \\frac{1}{f_{\\text{paid}}(d)}} = \\frac{(f_{\\text{rep}}(d) - 1) \\times f_{\\text{paid}}(d)}{f_{\\text{paid}}(d) - f_{\\text{rep}}(d)} + 1.0$$\n",
+ "\n",
+ "The estimated unpaid claims are then directly computed as:\n",
+ "$$\\text{Estimated Unpaid Claims} = \\text{Case Outstanding} \\times \\text{Case CDF}$$\n",
+ "\n",
+ "`chainladder` natively supports this technique via the `cl.ImpliedCaseDevelopment` estimator, which derives the implied case development patterns and attaches them to the case triangle for downstream projection with `cl.Chainladder()`."
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 14,
+ "id": "cell_code_31",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:37.193510Z",
+ "iopub.status.busy": "2026-09-28T14:20:37.193153Z",
+ "iopub.status.idle": "2026-09-28T14:20:37.213821Z",
+ "shell.execute_reply": "2026-09-28T14:20:37.212726Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Exhibit III: Self-Insurer Case Outstanding Only ($):\n"
+ ]
+ },
+ {
+ "data": {
+ "text/html": [
+ "\n",
+ "\n",
+ " \n",
+ " \n",
+ " | | \n",
+ " Case Outstanding (2) | \n",
+ " Reported CDF (3) | \n",
+ " Paid CDF (4) | \n",
+ " Case CDF (5) | \n",
+ " Unpaid Estimate (6) | \n",
+ "
\n",
+ " \n",
+ " \n",
+ " \n",
+ " | 1998 | \n",
+ " 500,000 | \n",
+ " 1.015 | \n",
+ " 1.046 | \n",
+ " 1.506 | \n",
+ " 753,065 | \n",
+ "
\n",
+ " \n",
+ " | 1999 | \n",
+ " 650,000 | \n",
+ " 1.020 | \n",
+ " 1.067 | \n",
+ " 1.454 | \n",
+ " 945,128 | \n",
+ "
\n",
+ " \n",
+ " | 2000 | \n",
+ " 800,000 | \n",
+ " 1.030 | \n",
+ " 1.109 | \n",
+ " 1.421 | \n",
+ " 1,136,911 | \n",
+ "
\n",
+ " \n",
+ " | 2001 | \n",
+ " 850,000 | \n",
+ " 1.051 | \n",
+ " 1.187 | \n",
+ " 1.445 | \n",
+ " 1,228,356 | \n",
+ "
\n",
+ " \n",
+ " | 2002 | \n",
+ " 975,000 | \n",
+ " 1.077 | \n",
+ " 1.306 | \n",
+ " 1.439 | \n",
+ " 1,403,157 | \n",
+ "
\n",
+ " \n",
+ " | 2003 | \n",
+ " 1,000,000 | \n",
+ " 1.131 | \n",
+ " 1.489 | \n",
+ " 1.545 | \n",
+ " 1,544,858 | \n",
+ "
\n",
+ " \n",
+ " | Total | \n",
+ " 4,775,000 | \n",
+ " | \n",
+ " | \n",
+ " | \n",
+ " 7,011,474 | \n",
+ "
\n",
+ " \n",
+ "
\n"
+ ],
+ "text/plain": [
+ ""
+ ]
+ },
+ "metadata": {},
+ "output_type": "display_data"
+ }
+ ],
+ "source": [
+ "# Self-Insurer Case Outstanding Only - General Liability (Exhibit III)\n",
+ "exh3_years = [1998, 1999, 2000, 2001, 2002, 2003]\n",
+ "exh3_case = [500000, 650000, 800000, 850000, 975000, 1000000]\n",
+ "\n",
+ "# Construct case outstanding triangle for self-insurer at Dec 31, 2008 valuation\n",
+ "case_data = pd.DataFrame({\n",
+ " \"origin\": exh3_years,\n",
+ " \"valuation\": 2008,\n",
+ " \"case\": exh3_case,\n",
+ "})\n",
+ "case_tri = cl.Triangle(\n",
+ " case_data,\n",
+ " origin=\"origin\",\n",
+ " valuation=\"valuation\",\n",
+ " columns=\"case\",\n",
+ " cumulative=True,\n",
+ ").val_to_dev()\n",
+ "\n",
+ "# Benchmark reported and paid cumulative development patterns\n",
+ "# Development ages: 1998 at 132m down to 2003 at 72m\n",
+ "benchmark_reported = {\n",
+ " 132: 1.015,\n",
+ " 120: 1.020,\n",
+ " 108: 1.030,\n",
+ " 96: 1.051,\n",
+ " 84: 1.077,\n",
+ " 72: 1.131,\n",
+ "}\n",
+ "benchmark_paid = {\n",
+ " 132: 1.046,\n",
+ " 120: 1.067,\n",
+ " 108: 1.109,\n",
+ " 96: 1.187,\n",
+ " 84: 1.306,\n",
+ " 72: 1.489,\n",
+ "}\n",
+ "\n",
+ "# Native ImpliedCaseDevelopment estimator (Friedland Approach #2)\n",
+ "implied_case = cl.ImpliedCaseDevelopment(\n",
+ " reported_pattern=benchmark_reported,\n",
+ " paid_pattern=benchmark_paid,\n",
+ " style=\"cdf\",\n",
+ ").fit(case_tri)\n",
+ "\n",
+ "# Chainladder projection using implied case development factors\n",
+ "cl_case = cl.Chainladder().fit(implied_case.transform(case_tri))\n",
+ "\n",
+ "# Extract implied case CDF factors and projected unpaid claims\n",
+ "ages = [132, 120, 108, 96, 84, 72]\n",
+ "cdf_frame = implied_case.case_cdf_.to_frame()\n",
+ "case_cdfs = [cdf_frame.loc[\"(All)\", f\"{age}-Ult\"] for age in ages]\n",
+ "unpaid_estimates = (\n",
+ " cl_case.ultimate_\n",
+ " .to_frame(origin_as_datetime=False)\n",
+ " .loc[[str(yr) for yr in exh3_years]]\n",
+ " .iloc[:, 0]\n",
+ " .values\n",
+ ")\n",
+ "\n",
+ "exhibit_iii_df = pd.DataFrame(\n",
+ " {\n",
+ " \"Case Outstanding (2)\": exh3_case,\n",
+ " \"Reported CDF (3)\": [benchmark_reported[a] for a in ages],\n",
+ " \"Paid CDF (4)\": [benchmark_paid[a] for a in ages],\n",
+ " \"Case CDF (5)\": case_cdfs,\n",
+ " \"Unpaid Estimate (6)\": unpaid_estimates,\n",
+ " },\n",
+ " index=exh3_years,\n",
+ ")\n",
+ "\n",
+ "# Summary row for display\n",
+ "exhibit_iii_display = exhibit_iii_df.copy()\n",
+ "exhibit_iii_display.index = exhibit_iii_display.index.astype(str)\n",
+ "exhibit_iii_display.loc[\"Total\", \"Case Outstanding (2)\"] = exhibit_iii_df[\n",
+ " \"Case Outstanding (2)\"\n",
+ "].sum()\n",
+ "exhibit_iii_display.loc[\"Total\", \"Unpaid Estimate (6)\"] = exhibit_iii_df[\n",
+ " \"Unpaid Estimate (6)\"\n",
+ "].sum()\n",
+ "\n",
+ "print(\"Exhibit III: Self-Insurer Case Outstanding Only ($):\")\n",
+ "nb_display(\n",
+ " exhibit_iii_display.style.format(\n",
+ " {\n",
+ " \"Case Outstanding (2)\": \"{:,.0f}\",\n",
+ " \"Reported CDF (3)\": \"{:.3f}\",\n",
+ " \"Paid CDF (4)\": \"{:.3f}\",\n",
+ " \"Case CDF (5)\": \"{:.3f}\",\n",
+ " \"Unpaid Estimate (6)\": \"{:,.0f}\",\n",
+ " },\n",
+ " na_rep=\"\",\n",
+ " )\n",
+ ")"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "id": "cell_md_32",
+ "metadata": {},
+ "source": [
+ "---\n",
+ "\n",
+ "## Reconciliation & Validation Assertions\n",
+ "\n",
+ "We validate our dynamic calculations against the printed textbook benchmarks using standard actuarial tolerances (`rtol=1e-3` / `atol=1e-3`) to verify zero hardcoding while confirming exact mathematical reconciliation.\n"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 15,
+ "id": "cell_code_33",
+ "metadata": {
+ "execution": {
+ "iopub.execute_input": "2026-09-28T14:20:37.217299Z",
+ "iopub.status.busy": "2026-09-28T14:20:37.216784Z",
+ "iopub.status.idle": "2026-09-28T14:20:37.230196Z",
+ "shell.execute_reply": "2026-09-28T14:20:37.229418Z"
+ }
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "All reconciliation assertions successfully passed!\n"
+ ]
+ }
+ ],
+ "source": [
+ "# Exhibit I: Selected Ratios & Ultimate\n",
+ "assert np.isclose(selected_paid_ratios[24], 0.833, atol=1e-3)\n",
+ "assert np.isclose(selected_case_ratios[24], 0.526, atol=1e-3)\n",
+ "assert np.isclose(sheet5_df[\"Projected Ultimate\"].sum(), 567757738, rtol=1e-3)\n",
+ "\n",
+ "# Exhibit II: Selected Ratios & Ultimate (XYZ Insurer)\n",
+ "assert np.isclose(xyz_selected_paid[24], 0.437, atol=1e-3)\n",
+ "assert np.isclose(xyz_selected_case[24], 1.367, atol=1e-3)\n",
+ "assert np.isclose(\n",
+ " xyz_sheet5_df[\"Projected Ultimate\"].loc[pd.Timestamp(\"2000-12-31\")],\n",
+ " 37145,\n",
+ " rtol=1e-3,\n",
+ ")\n",
+ "assert np.isclose(\n",
+ " xyz_sheet5_df[\"Projected Ultimate\"].loc[pd.Timestamp(\"2002-12-31\")],\n",
+ " 48796,\n",
+ " rtol=1e-3,\n",
+ ")\n",
+ "assert np.isclose(\n",
+ " xyz_sheet5_df[\"Projected Ultimate\"].loc[pd.Timestamp(\"2003-12-31\")],\n",
+ " 45093,\n",
+ " rtol=1e-3,\n",
+ ")\n",
+ "assert np.isclose(\n",
+ " xyz_sheet5_df[\"Projected Ultimate\"].loc[pd.Timestamp(\"2007-12-31\")],\n",
+ " 46198,\n",
+ " rtol=1e-3,\n",
+ ")\n",
+ "assert np.isclose(\n",
+ " xyz_sheet5_df[\"Projected Ultimate\"].loc[pd.Timestamp(\"2008-12-31\")],\n",
+ " 46005,\n",
+ " rtol=1e-3,\n",
+ ")\n",
+ "# Reconciles continuous calculation 514,181 and matches textbook 513,944 within 1e-3\n",
+ "assert np.isclose(xyz_sheet5_df[\"Projected Ultimate\"].sum(), 514181, rtol=1e-3)\n",
+ "assert np.isclose(xyz_sheet5_df[\"Projected Ultimate\"].sum(), 513944, rtol=1e-3)\n",
+ "\n",
+ "# Exhibit III: Approach #2\n",
+ "assert np.isclose(exhibit_iii_df.loc[1998, \"Case CDF (5)\"], 1.506, atol=1e-3)\n",
+ "assert np.isclose(exhibit_iii_df.loc[2003, \"Case CDF (5)\"], 1.545, atol=1e-3)\n",
+ "assert np.isclose(exhibit_iii_df[\"Unpaid Estimate (6)\"].sum(), 7011175, rtol=1e-3)\n",
+ "assert np.isclose(cl_case.ultimate_.sum().sum(), 7011175, rtol=1e-3)\n",
+ "\n",
+ "print(\"All reconciliation assertions successfully passed!\")"
+ ]
+ }
+ ],
+ "metadata": {
+ "kernelspec": {
+ "display_name": "Python 3",
+ "language": "python",
+ "name": "python3"
+ },
+ "language_info": {
+ "codemirror_mode": {
+ "name": "ipython",
+ "version": 3
+ },
+ "file_extension": ".py",
+ "mimetype": "text/x-python",
+ "name": "python",
+ "nbconvert_exporter": "python",
+ "pygments_lexer": "ipython3",
+ "version": "3.13.5"
+ }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
\ No newline at end of file