Reinsurance losses from last month’s Chilean earthquake and European windstorm could push some reinsurers into the red for the first quarter of 2010, says Moody’s Investors Service in a report issued Friday.

Sixteen global reinsurers have reported about $3.5 billion in net losses before tax from the Chilean earthquake and Windstorm Xynthia, the Moody’s report said.

While first quarter 2010 results “will have many moving pieces, including the possibility of favorable loss reserve development, we would expect a number of reinsurers to post both operating and net losses for the quarter,” the report states.

In addition, the report says, given the size of the losses, the uncertainty surrounding initial loss estimates and the uncertainty about the severity of this year’s hurricane season, Moody’s expects reinsurers “to take a hard look” at their announced share repurchase plans.

In addition to reporting their own reinsurance losses, the firms released estimates of the total primary insurance loss for the Feb. 27 quake that range from $4 billion to $10 billion, Moody’s said. Primary insurance loss estimates for the windstorm range from $2 billion to $4 billion, Moody’s said.

The rating agency noted, however, “much uncertainty remains surrounding these loss estimates, as we believe that most reinsurers are making educated guesses based on market share percentages of possible industrywide insured losses.”

Copies of the report, “Reinsurers’ Catastrophe Losses from Chilean Earthquake and Windstorm Xynthia to Pressure 1Q2010 Earnings,” is available at www.moodys.com.