The nation's 3,000 property-and-casualty insurers, including MBIA and Allstate, suffered a combined 53% decline in profits during the first half of 2008, dragged down by the first industry-wide underwriting loss in five years.

Insurers' earnings dropped to $16 billion in the six months through June 30 from $35 billion in the same period a year earlier.

Losses in underwriting and investments delivered a double blow. The industry has been limping through a weak market for several quarters, and a rebound isn't expected for several more. First-half premium volume was down for the first time since 2005, decreasing to $220.5 billion from $221.3 billion because of depressed prices. Claims jumped by 13.6%, or $20 billion. Consequently, the industry booked a net loss on core underwriting of $5 billion, compared with a gain of $15.7 billion in the year-earlier period.

On top of the extraordinary first-half underwriting loss, invested assets of all P&C insurers declined 14% to $27 billion from $32 billion. The value of the industry's $845 billion bond holdings increased 0.2%, the smallest gain since a decline in 2000. Likewise, common stock holdings slumped 5.8% to $326 billion from $346 billion.

The table below includes the companies with the largest year-over-year net losses.

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Allstate, a division of Allstate Insurance Group ( ALL), reported a profit drop of $1.5 billion, more than any other insurer. The percentage decline was 61.5%. The lower earnings at the third-largest U.S. property-casualty insurer came equally from underwriting and investment losses. Other Allstate affiliates, Allstate Texas Lloyds and Allstate Fire and Casualty Insurance Co., are major homeowner insurers in Texas. Results for both insurers remained flat during the first half of the year, though claims stemming from Hurricane Ike probably will dent underwriting.

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