Exhibit 99.1

ACE REPORTS RECORD THIRD QUARTER OPERATING INCOME OF

$759 MILLION, PREMIUM REVENUE UP 31% AND COMBINED RATIO OF 90.3%;

REALIZED AND UNREALIZED LOSS CONTRIBUTES TO

BOOK VALUE PER SHARE DECLINE OF 1%;

OPERATING INCOME GUIDANCE INCREASED TO $6.55-$6.75 PER SHARE

ZURICH, October 25, 2011 — ACE Limited (NYSE: ACE) today reported a net loss for the quarter ended September 30, 2011, of $0.09 per share, compared with net income of $1.97 per share for the same quarter last year;⁽¹⁾ income excluding net realized gains (losses) was $2.22 per share, compared with $2.01 per share for the same quarter last year.⁽²⁾ Annualized operating return on average equity for the quarter was 13.6%.⁽³⁾ The property and casualty (P&C) combined ratio for the quarter was 90.3%. The quarter was marked by financial market volatility in the credit, equity and foreign exchange markets, which impacted net income and book value. A net realized and unrealized loss contributed to a book value per share decline of 1%. Financial market volatility impacted the company’s variable annuity reinsurance business resulting in a net loss of about $660 million, which comprised a realized loss of $706 million related to the change in fair-value liabilities, offset by $45 million in operating income. Book value is up 3% for the year.

Third Quarter Summary

(in millions, except per share amounts)

(Unaudited)

Net income for the nine months ended September 30, 2011, was $2.45 per share, compared with $6.18 per share for the same period in 2010. For the nine months ended September 30, 2011, income excluding net realized gains (losses) was $5.02 per share, compared with $5.73 per share for 2010. Book value increased $776 million, up 3% from December 31, 2010. The P&C combined ratio for the nine months ended September 30, 2011, was 95.2%.

Nine Months Summary

(in millions, except per share amounts)

(Unaudited)

Evan G. Greenberg, Chairman and Chief Executive Officer of ACE Limited, commented: “ACE had outstanding operating results in what were very difficult financial market conditions. All principal businesses performed well and contributed positively to the operating results in the quarter. Revenue increased 31% and after-tax operating income was $759 million, up 10% and a record for our company. Our performance in the quarter was led by excellent current accident year underwriting results that benefited from both underwriting discipline and risk management. We also had strong contributions from our recent acquisitions and very good growth in investment income driven by portfolio construction and positive cash flow. The strength of our well-balanced portfolio of businesses was in evidence, including commercial P&C globally, personal accident and life, crop and our global presence, particularly in faster growing regions such as Asia and Latin America.

“As a result of an historic drop in interest rates – the lowest level in over 100 years – and an equity market correction driven by Federal Reserve action and a flight to safety by investors, we incurred a substantial charge to book value from a negative mark to market in our variable annuity reinsurance business and our corporate fixed income investment portfolio. In our judgment, the majority of this mark will be transient and will reverse over time making a positive contribution to book value in future quarters.

“ACE is in excellent shape and we remain quite confident about our prospects for the fourth quarter and beyond.”

Operating highlights for the quarter ended September 30, 2011, were as follows: ⁽¹⁾

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Details of our financial results for our business segments are available in the ACE Limited Financial Supplement. Key segment items for the quarter ended September 30, 2011, include:

Please refer to the ACE Limited Financial Supplement, dated September 30, 2011, which is posted on our website in the Investor Information section, and access Financial Reports for more detailed information on individual segment performance, together with additional disclosure on reinsurance recoverable, loss reserves, investment portfolio and capital structure.

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The company is increasing earnings guidance for full-year 2011. Operating income after tax is now expected to range between $6.55 and $6.75 per share for the full year. This includes $630 million after tax in catastrophe losses for the first three quarters, plus $75 million after tax in catastrophe losses for the fourth quarter. The guidance also includes $335 million of after-tax positive prior period development reflected in the first three quarters. There is no prior period development included in our guidance for the fourth quarter.

ACE will host its third quarter earnings conference call and webcast on Wednesday, October 26, 2011, beginning at 8:30 a.m. Eastern. The earnings conference call will be available via live and archived webcast at www.acegroup.com or by dialing 800-967-7185 (within the United States) or 719-457-2654 (international); passcode 9247852. Please refer to the ACE Limited website in the Investor Information section under Calendar of Events for details. A replay of the call will be available for approximately one month. To listen to the replay, dial: 888-203-1112 (in the United States) or 719-457-0820 (international); passcode 9247852.

The ACE Group is a global leader in insurance and reinsurance serving a diverse group of clients. Headed by ACE Limited (NYSE:ACE), a component of the S&P 500 stock index, the ACE Group conducts its business on a worldwide basis with operating subsidiaries in more than 50 countries. Additional information can be found at: www.acegroup.com

⁽¹⁾ All comparisons are with the same period last year unless specifically stated.

⁽²⁾ Non-GAAP Financial Measures:

Operating Income or Income excluding net realized gains (losses), net of tax is a common performance measurement for insurance companies. We believe this presentation enhances the understanding of our results of operations by highlighting the underlying profitability of our insurance business. We exclude net realized gains (losses) and net realized gains (losses) included in Other income (expense) related to partially-owned entities because the amounts of these gains (losses) do not relate to their respective operations.

Underwriting income is calculated by subtracting losses and loss expenses, policy benefits, policy acquisition costs and administrative expenses from net premiums earned. We use underwriting income and operating ratios to monitor the results of our operations without the impact of certain factors, including net investment income, other income (expense), interest and income tax expense and net realized gains (losses). Life underwriting income includes net investment income and gains (losses) from separate account assets that do not qualify for separate account reporting under generally accepted accounting principles (GAAP). We believe the use of these measures enhances the understanding of our results of operations by highlighting the underlying profitability of our insurance business.

See reconciliation of Non-GAAP Financial Measures on page 23 in the financial supplement. These measures should not be viewed as a substitute for net income determined in accordance with GAAP.

⁽³⁾ Calculated using income excluding net realized gains (losses) divided by average shareholders’ equity for the period excluding unrealized gains (losses) on investments and the deferred tax component included in shareholders’ equity. To annualize a quarterly rate, multiply by four.

⁽⁴⁾ Book value per common share is shareholders’ equity divided by the shares outstanding. Tangible book value per common share is shareholders’ equity less goodwill and other intangible assets divided by the shares outstanding.

⁽⁵⁾ For the three months ended September 30, 2011, weighted-average shares outstanding used in calculating net loss per share excludes the effect of dilutive securities of 2,464,705 shares. In periods where a net loss is recognized, inclusion of incremental dilution is anti-dilutive.

NM – not meaningful comparison

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Cautionary Statement Regarding Forward-Looking Statements:

Forward-looking statements made in this press release, such as those related to company performance and guidance, recent corporate developments and acquisitions, our products and product mix, economic outlook and insurance market conditions, reflect our current views with respect to future events and financial performance and are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Such statements involve risks and uncertainties, which may cause actual results to differ materially from those set forth in these statements. For example, our forward-looking statements could be affected by competition, pricing and policy term trends, the levels of new and renewal business achieved, the frequency of unpredictable catastrophic events, actual loss experience, uncertainties in the reserving or settlement process, integration activities and performance of acquired companies, new theories of liability, judicial, legislative, regulatory and other governmental developments, litigation tactics and developments, investigation developments and actual settlement terms, the amount and timing of reinsurance recoverable, credit developments among reinsurers, rating agency action, possible terrorism or the outbreak and effects of war, and economic, political, regulatory, insurance and reinsurance business conditions, as well as management’s response to these factors, and other factors identified in our filings with the Securities and Exchange Commission. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the dates on which they are made. We undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

(tables to follow)

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ACE Limited

Summary Consolidated Balance Sheets

(in millions of U.S. dollars, except per share data)

(Unaudited)

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ACE Limited

Summary Consolidated Financial Data

(in millions of U.S. dollars, except share, per share data, and ratios)

(Unaudited)

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ACE Limited

Consolidated Supplemental Segment Information

(in millions of U.S. dollars)

(Unaudited)

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