ZURICH (Bloomberg) — Swiss Reinsurance Co., the world’s biggest reinsurer, said its property and casualty reinsurance portfolio grew by 14 percent in the January renewals following its acquisition of General Electric Co.’s Insurance Solutions unit.The premium volume grew to 10.3 billion Swiss francs ($8.2 billion) and Swiss Re was able to retain 70 percent of Insurance Solutions’ non-life business in January’s renewal period, the Zurich-based reinsurer said yesterday in an e-mailed statement.

The reinsurer and rivals including Munich Re and Hannover Re are trying to maintain premium levels this year following last year’s almost complete absence of costly natural disasters.

Insured losses due to storms reached a record of $87 billion in 2005, according to Munich Re. They shrank to about $250 million in 2006.

Premium volume is the combination of rate changes, renewed and canceled business and new business. Renewals are a key gauge for a reinsurer’s future growth. Reinsurers help primary insurers like Allianz SE or Axa SA shoulder risks for clients.

Hannover Re, the world’s fourth-biggest reinsurer, last week said premiums from property and casualty contracts renewed in January rose 2 percent, boosted by a takeover of its majority owner Talanx AG that helped its German business.

Munich Re, the second-largest reinsurer, on January 30 reported a 3 percent decline in premiums from property and casualty contracts renewed in January.

Swiss Re, which bought Insurance Solutions for $7.4 billion in June, is scheduled to report fourth-quarter and full-year 2006 figures on March 1.