Chubb (CB)

Business Overview

Chubb underwrites better than any of the six insurers profiled on this site, and it is also the largest of them: market capitalisation was roughly $129.8 billion as of 10 June 2026. The franchise spans global commercial specialty, middle-market commercial, and high-net-worth personal lines.

FY2025 combined ratio was 85.7%, well inside the strong-underwriting screen of below 95% and far below the preliminary US industry prints of 92.2% (AM Best) and 92.9% (Verisk). Lower is better here: the ratio is claims plus expenses as a share of premium, so anything under 100% is an underwriting profit. The margin comes from choosing which risks to write, across many geographies.

Return on equity was 15.0% on a GAAP net-income basis for FY2025, with core operating ROE of 13.7% in the same release. Book value per share excluding AOCI ended 2025 at $201.31, and the P/BV vs ROE guide shows how a return at that level is read against the cost of equity.

How the Numbers Read

The combined ratio is the P&C scoreboard: loss ratio plus expense ratio, with investment income sitting outside. Chubb's 85.7% implies an underwriting profit of 14.3 cents on every premium dollar before the investment portfolio contributes. Progressive ran 87.4% in FY2025, Travelers 89.9% and AIG's General Insurance business 90.1%, so Chubb sits about four points clear of the weakest of the four. All four are calendar-year figures, which matters for the next paragraph.

Investment income amplifies the underwriting result. FY2025 net investment income was $6,947 million on an adjusted pre-tax basis ($6,465 million pre-tax). Average book yield on fixed income investments was 5.1%, the highest of the six insurers here. Book yield is what the bonds already owned are earning, so it moves slowly: a rate move changes only the money being reinvested that year.

Part of that 85.7% is not this year's work. Prior-year reserve development, or PYD, was favourable $1,133 million pre-tax in FY2025 ($858 million after-tax), meaning claims from earlier years settled for less than Chubb had set aside, and the difference is released into this year's loss ratio. Against roughly $46 billion of P&C premium earned, that release is worth about two and a half points of the combined ratio. Strip it and the underwriting Chubb actually did in 2025 reads closer to 88%. The reserve development guide makes the wider point: a long run of releases says the company has booked reserves conservatively in the past, not that today's reserves are adequate. US liability lines swung to $7.8 billion of adverse development in calendar 2024 after years of the opposite.

Premiums arrive before claims leave, so float scales with premium volume. Underwriting profit makes that float cheaper than any bank deposit. Chubb's sub-90% combined ratio means the cost of float is deeply negative in underwriting terms, and the 5.1% fixed-income book yield compounds on a growing balance sheet. The float guide shows why raw yields cannot be ranked across filers without reading each label. Chubb's 5.1% is a book yield on fixed income only.

Valuation Framework

Insurer equity research starts with P/BV on ex-AOCI book against sustainable ROE. At steady state analysts use P/BV ≈ ROE ÷ cost of equity as a sanity check, with 10.0% as the nominal cost of equity. For Chubb the input question is durability: a 15.0% return earned on an 85.7% combined ratio is worth more if the underwriting holds through cycles than if one good year produced it.

What to Watch in the Financials

Combined ratio versus the 85 to 86% run rate. Any sustained drift toward 90% would still beat the industry, but it would narrow the float advantage behind the ROE lead.

PYD sign and magnitude. Favourable $1,133 million pre-tax in FY2025 helped the loss ratio. Adverse development on a name with Chubb's history would be a sentiment shock even if the absolute dollars were manageable.

Book yield versus reinvestment. 5.1% fixed-income book yield reflects the portfolio already on the balance sheet. New money rates and credit spread moves flow through with a lag, so NII growth against average invested assets says more than a spot Treasury move.

Core operating ROE (13.7%) versus GAAP (15.0%). The gap is the usual noise between operating and reported equity returns. If GAAP ROE falls toward core while the combined ratio stays strong, look to AOCI or catastrophe load for the cause.

Key Risks

Large-loss and catastrophe frequency. Industry cat losses added an estimated 7.6 points to the 2025 US P&C combined ratio. Chubb's global commercial book carries natural catastrophe exposure that a single benign year cannot erase from pricing.

Social inflation and liability lines. The $7.8 billion adverse industry PYD in calendar 2024 concentrated in liability. Chubb's favourable FY2025 development does not immunise future accident years from the same trend.

ROE slip. A year where the combined ratio normalises toward 90% without a matching investment-income offset would pull GAAP ROE out of the mid-teens.