LONDON (Bloomberg) — Bermuda-based Catlin Group Plc, owner of the largest insurance unit at Lloyd's of London, said premium revenue rose in the first nine months of the year as international sales climbed.

Gross written premiums advanced 4.5 percent to $2.86 billion from $2.74 billion a year earlier, the company said yesterday in a statement.

"We expect significantly improved conditions for most classes of reinsurance and some classes of insurance by year-end renewals," chief executive officer Stephen Catlin said in the statement. "Rates for many other classes of insurance will begin to rise later in 2009."

Lloyd's insurers have been hurt this year by declining investment returns caused by falling stock markets and hurricanes Ike and Gustav, which cost the insurance industry about $10 billion when they struck the Gulf Coast in September, according to data from Insurance Services Office Inc. The hurricanes, which cost Catlin $200 million, may cause premiums to rise next year as customers look to protect their assets from natural disasters.

Investments in the period to September 30 dropped 0.9 percent, compared with a 3.2 percent gain a year earlier.