Exhibit 99.1

ACE REPORTS FIRST QUARTER NET INCOME OF $259 MILLION,

OPERATING INCOME OF $268 MILLION AND

NET AFTER-TAX CATASTROPHE LOSSES OF $443 MILLION;

BOOK VALUE AND TANGIBLE BOOK VALUE UP 2%

ZURICH, May 4, 2011 — ACE Limited (NYSE: ACE) today reported net income for the quarter ended March 31, 2011, of $0.76 per share, compared with $2.22 per share for the same quarter last year.⁽¹⁾ Income excluding net realized gains (losses) was $0.79 per share, compared with $1.70 per share for the same quarter last year.⁽²⁾ Net after-tax catastrophe losses for the first quarter of 2011 were $443 million, including reinstatement premiums, or $1.30 per share, compared with $149 million, or $0.44 per share, for the first quarter of 2010. Book value increased $402 million, or 2%, during the quarter. Book value per share of $69.33 and tangible book value per share of $55.31 were up 1% from December 31, 2010. Annualized operating return on average equity for the quarter was 4.9%.⁽³⁾ The property and casualty (P&C) combined ratio for the quarter was 105.0%.

First Quarter Summary

(in millions, except per share amounts)

(Unaudited)

Evan G. Greenberg, Chairman and Chief Executive Officer of ACE Limited, commented: “ACE had a very good quarter that was overshadowed by significant catastrophe losses. We produced $268 million in operating income and grew book value 2%. Our ROE and combined ratio were 4.9% and 105%, respectively. Excluding the catastrophe loss impact, our book value growth, ROE and current accident year combined ratio were 4%, 13%, and 91.8%, respectively. I believe this speaks to the health of our business, the strength of our risk management and the benefit of our broadly diversified business.

“Our revenue growth was better than we originally anticipated when we planned the year and the renewal persistency of our business was excellent. We also benefited in the quarter from positive client payroll and sales growth due to improved economic conditions. Finally, rates for our renewal business declined at the slowest pace we have experienced in a number of quarters.

“We are more confident today about our prospects for full-year premium growth than we were last quarter and now believe growth will be between upper single-digit and low double-digit. Not included in our projections, if markets firm in any individual geography or class as a result of the catastrophes and reach a point where we find the risk-reward attractive, we are well positioned to take advantage.”

Operating highlights for the quarter ended March 31, 2011, were as follows: ⁽¹⁾

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Details of the financial results for the company’s business segments are available in the ACE Limited Financial Supplement. Key segment items for the quarter ended March 31, 2011, include:

In light of the level of first quarter catastrophe losses, the company is adjusting guidance for the year. Operating income is now expected to range between $5.40 and $5.70 per share for the full year. This includes $443 million in catastrophe losses for the first quarter, plus $250 million in catastrophe losses for the balance of the year. The guidance also includes $74 million of after-tax positive prior period development reflected in the first quarter as well as an adjustment for the estimated increase to the investment income run rate.

Please refer to the ACE Limited Financial Supplement, dated March 31, 2011, which is posted on the company’s 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.

ACE will host its first quarter earnings conference call and webcast on Thursday, May 5, 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 888-318-7470 (within the United States) or 719-325-2392 (international); passcode 7918119. 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 7918119.

Celebrating 25 years of insuring progress, the ACE Group is a global leader in insurance and reinsurance serving a diverse group of clients. Headed by ACE Limited (NYSE:ACE), 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.

Income excluding net realized gains (losses), catastrophe losses and prior period development, net of tax is a non-GAAP measure. We present income excluding net realized gains (losses), catastrophe losses and prior period development, net of tax in order that users of our financial information can view and assess the specific impact of catastrophe losses and prior period development on the relevant periods and because of the variance in those amounts in the comparable periods. We believe this separate presentation is meaningful and useful for users of our financial information.

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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. 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 24 in the financial supplement. These measures should not be viewed as a substitute for net income determined in accordance with generally accepted accounting principles (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⁾ For Q1 2010, prior period development is net of $31 million, after-tax, for the annual crop insurance profit-sharing commission that is included in the expense ratio.

⁽⁵⁾ 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.

NM – not meaningful comparison

Cautionary Statement Regarding Forward-Looking Statements:

Forward-looking statements made in this press release, such as those related to company performance and guidance, 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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