(Bloomberg) ? Allstate Corp. and State Farm Mutual Automobile Insurance Co. are among five insurers and reinsurers that may have their credit ratings cut by Fitch Ratings because of Hurricane Katrina claims.

The five companies, which also include Horace Mann Educators Corp., Montpelier Re Holdings Ltd. and PXRE Group Ltd., may have to pay claims amounting to ?a material percentage of their equity base,? Fitch said in a statement.

The ratings on all but Horace Mann are also being reviewed by Standard & Poor?s.

Katrina slammed the US Gulf Coast last month, dislodging oil rigs and breaking levees to flood 80 percent of New Orleans. Katrina may generate $40 billion to $60 billion in insured losses, making it the most expensive catastrophe ever, according to storm modeller Risk Management Solutions Inc.

State Farm and Allstate, the two largest US home and auto insurers, haven?t published loss estimates, nor has competitor Horace Mann.

Montpelier Re, a Bermuda-based reinsurer, said yesterday it expected $450 million to $675 million in losses, as much as 45 percent of its shareholders? equity.

Reinsurer PXRE said on September 11 that claims may cost $235 million, after taxes, leading to a net loss of as much as $100 million for 2005.

Reinsurers share the claims and premiums of insurers.

The stock of Northbrook, Illinois-based Allstate fell 66 cents, or 1.2 percent, to $53.42 and Horace Mann, based in Springfield, Illinois, rose 10 cents, or 0.5 percent, to $20.29 in New York Stock Exchange composite trading.

Montpelier Re fell 22 cents to $25.77 after declining 17 percent yesterday and Bermuda-based PXRE rose 24 cents, or 1.3 percent, to $19.35. State Farm is owned by its policyholders.

?Allstate has substantial financial strength and liquidity to support our commitments from Hurricane Katrina,? said company spokesman Michael Trevino.

PXRE plans to raise capital through ?some sort of equity debt? offering, Chief Financial Officer John Modin said in an interview.