NEW YORK (Bloomberg) — Arch Capital Group Ltd., a Bermuda-based insurer, said fourth-quarter operating profit probably dropped after the company increased its loss estimate for Hurricane Ike.

Operating profit in the period was $75 million to $90 million, compared with $220.6 million a year earlier, the insurer said yesterday in a statement distributed by Business Wire.

Arch Capital, led by Constantine Iordanou, joins Validus, PartnerRe and IPC Holdings in raising loss estimates for Ike, the third-costliest US storm after Katrina in 2005 and Andrew in 1992. Ike and a smaller storm, Hurricane Gustav, struck the Gulf Coast in September, part of six consecutive named storms to make U.S. landfall. Gustav slammed into Louisiana on September 1, sparing New Orleans a direct hit. Ike struck Galveston, Texas, two weeks later.

Arch Capital raised its loss estimate for Ike by $160 million, according to the statement. The insurer said in September that Ike and Gustav would cost the company $105 million to $180 million.

The industry may lose $18 billion to $21 billion on Ike, Arch Capital said yesterday. That forecast is up from the $8 billion to $12 billion in costs for both storms that Arch Capital assumed in September.