NEW YORK (Bloomberg) — Warren Buffett's Berkshire Hathaway Inc. and Swiss Reinsurance Co. are among reinsurers that posted a second straight increase in policyholders' surplus in the US as weather-related claims dropped and prices rose.

The combined surplus of 19 reinsurers climbed 12 percent in the three months ended September 30 to $74.1 billion, the Reinsurance Association of America said today in a report. The surplus, a measure of assets minus liabilities, has improved for two quarters after shrinking in the previous six.

"Prices going up helped," Paul Newsome, an analyst at Sandler O'Neill & Partners LP, said yesterday in an interview. "The level of catastrophe losses being relatively low helps as well."

Berkshire Hathaway's National Indemnity Co. posted a surplus gain of 21 percent to $34.4 billion, and the Omaha Nebraska-based company's General Re had a 10 percent surplus increase to $9.93 billion. Swiss Re, the world's second-largest reinsurer, posted a 3.7 percent surplus gain to $6.46 billion at its US unit after the Zurich-based company swung to profit in the third quarter.

Reinsurers provide coverage to primary carriers, protecting them from large claims including catastrophes. Hurricanes Ike and Gustav contributed last year to $27 billion in catastrophic losses for the industry, the costliest year since Hurricane Katrina struck in 2005. Ike was the third most expensive US storm in history, costing $12.5 billion, according to the Insurance Information Institute.

Willis Re, the reinsurance unit of broker Willis Group Holdings Ltd., said in a July report that US catastrophe reinsurance prices at midyear were up 10 to 15 percent.