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NEW YORK (CNNMoney) -- Travelers Companies stock slid more than 3% Friday after the insurer warned it would face $1 billion in catastrophic losses stemming from the storms and floods in the Midwest and South.
As a result of those losses, the company said it would also slow its stock buyback program. Travelers (TRV, Fortune 500) stock fell 3.1% to settle at $59.21.
Travelers disclosed the expected losses in a filing with the Securities and Exchange Commission on Friday.
"As a matter of prudence," Travelers said it was limiting its stock buyback in the second quarter to less than $250 million.
The company said it would likely discuss the issues at its investor conference, which was taking place in New York on Friday.
Travelers was the biggest drag on the blue-chip Dow index in afternoon trading, and the sell-off spilled over to other stocks in the insurance sector. Allstate (ALL, Fortune 500), Metlife (MET, Fortune 500) and Principal Financial (PFC) all fell by about 1.8% or more.
The Dow fell below 12,000 for the first time in three months. The selling was broad, with the Nasdaq erasing all of its gains for the year.
Later Friday, MetLife disclosed its own losses as a result of the storms: an estimated $160 million to $180 million. 
