The impact of second-quarter catastrophes on insurers isbeginning to be seen, as four separate companies cited cat lossesas the primary reason for their drop in net income.

The Travelers Cos. was the firstof the four to report results, and it also suffered the biggestimpact from catastrophes. The insurer reports a second-quarter netloss of $364 million, driven by $1.09 billion in catastrophelosses, after tax. Catastrophes added more than 30 points toTravelers' combined ratio of 125.

Travelers CEO Jay Fishman says losses due to extreme tornadoesand hail during the second quarter were “the equivalent of losseswe would expect from a 1-in-100-year hurricane.” Nevertheless, hesays Travelers' capital “remained generally unchanged.”

Warren, N.J.-based international-insurer Chubb Corp. saw $329million in catastrophe losses in the quarter, driven by storms inthe U.S.—especially in Alabama, Missouri and North Carolina. Thelosses contributed to a 19 percent drop in 2011 second-quarter netincome, which fell to $419 million.

Catastrophe losses added 11.3 points to Chubb's combined ratio,which climbed to 94.9 compared to 90.4 in the 2010 secondquarter.

“It was the highest second-quarter [catastrophe] impact in thehistory of Chubb by a wide margin,” says Dino Robusto, president ofpersonal lines, during a conference call.

Bermuda-based specialty-insurer and reinsurer Arch Capital GroupLtd.'s 2011 second-quarter net income dropped more than 61 percent,to $91.9 million, compared to the same period a year ago ascatastrophes caused $95 million in losses.

Arch says $81.5 million consists of cat events that occurredduring the quarter, while the remaining $13.5 million isattributable to increases in loss estimates for 2011 first-quarterevents. The $95 million in cat losses compares to $7 million in catlosses for the 2010 second quarter. 

Arch's combined ratio was 99.6, up from 90 in the 2010 secondquarter. 

W.R. Berkley Corp. says second-quarter net income fell about 25percent, to about $83.1 million, as catastrophes during the periodmore than doubled compared to last year.

Catastrophe losses, driven by weather events in the U.S. inApril and May, were $63 million after reinsurance andreinstatements. Cat losses were $30 million during the 2010 secondquarter.

The Greenwich, Conn.-based specialty insurer's combined ratiofor the second quarter was 101.1.