Indianapolis-based Baldwin & Lyons Inc. turned a profit in the fourth quarter, but it wasn’t enough to erase a dismal 2011 plagued by catastrophic losses.

The auto and trucking fleet insurer said Thursday morning that it earned $5.5 million, or 37 cents per share, in the quarter, down from $10.3 million, or 69 cents per share, in the same period of 2010.

Baldwin & Lyons lost $28.2 million in 2011 after earning $25 million the previous year. It suffered losses in the first three quarters of 2011.

Quarterly revenue rose from $67.7 million to $71.4 million in the latest quarter, but annual revenue fell from from $249.5 million in 20101 to $243.6 million in 2011.    

Baldwin & Lyons said profit in the fourth quarter was dragged down by $5 million in after-tax losses sustained in connection with flooding in Thailand that began in October and continued through the rest of the year.

Quarterly investment gains also dropped, from $3.8 million to $2 million.

During the year, the insurer paid for significant damage its policyholders sustained from Hurricane Irene, which ravaged the East Coast in August, and other storms in the United States, as well as continuing claims from the March earthquake in Japan.

For 2011, major catastrophes resulted in about $43 million in after-tax losses compared to about $17 million during 2010, the company said.

The insurer did see a rise in business, with written premiums increasing 12 percent in the quarter and 13 percent for the year.

Baldwin & Lyon’s common stock closed Wednesday at $23 per share, its highest closing price since Nov. 15.