Travelers Cos., the only property insurer in the Dow Jones Industrial Average, spent a record amount on share repurchases this quarter as it benefits from lower costs tied to the most severe natural disasters.

The insurer bought back $633 million in stock from July 1 through yesterday, bringing the total this year to about $1.2 billion, Chief Executive Officer Jay Fishman, 60, said today at a Barclays Plc conference. Catastrophe costs this quarter have been about $30 million after tax, he said.

Travelers and other U.S. property insurers are benefiting this year from calmer weather after tornadoes and other natural disasters caused claims costs to spike in recent years. Humberto became the first hurricane of the Atlantic season today, missing by three hours the record for the tardiest such storm.

“The third quarter as everyone knows has been benign and quiet from a windstorm perspective,” Fishman said at the conference. The New York-based insurer has bought back more than half its stock since the middle of 2006, he said.

Travelers typically limited repurchases in the third quarter, during the peak of the Atlantic hurricane season. The last time the insurer bought back more than $600 million in shares in a third quarter was in 2010.

The total this period is the most in any quarter since the last three months of 2011, when Travelers bought back $1.2 billion in stock. The company was formed by the 2004 merger of Travelers Property Casualty Corp. and St. Paul Cos.

Catastrophe costs at the insurer were $59 million in last year’s third quarter and $394 million in the period in 2011. The Atlantic hurricane season runs from June 1 to Nov. 30.

Travelers rose 0.6 percent to $83.01 at 10:20 a.m. in New York, extending its gain to 16 percent this year. That matches the advance for the 30-company Dow average.

Editor: Dan Kraut