The company, based in Zurich, said net income surged to $973 million, or $2.84 a share, in the three months ended March 31. That compares with net income of $250 million, or 73 cents a share, in the prior-year quarter.
The latest results included $272 million in net realized gains, primarily from variable annuity reinsurance derivatives. Stripping out the one-time gains, ACE earned $2.05 per share.
That beat analysts' consensus forecast, which called for earnings of $1.88 a share, according to FactSet.
CEO Evan Greenberg noted that ACE and much of the rest of the insurance industry benefited during the quarter from relatively light catastrophe losses compared to 2011.
Total pre-tax catastrophe losses, including reinstatement premiums, were $19 million, compared with $489 million in all of last year.
ACE estimates after-tax catastrophe losses will total $325 million for the last three quarters of this year.
The company also benefited from improved pricing for its insurance products. Rates on its U.S. business rose 3.6 percent on average during the quarter.
ACE's net premiums written grew 3.7 percent to $3.57 billion for the quarter.
Greenberg expects the company's premium growth rate will accelerate as the year progresses.