Overall, the top 25 U.S. reinsurers recorded a 94.2 combined ratio for 2010, up nearly 2 points higher than a 92.3 ratio recorded in 2009.

Only seven of the 25 reinsurers boosted reserves for prior accident years in 2010. Everest Re and Swiss Re America were among the seven, while 18 others recorded takedowns ranging from a low of $3.6 million (Toa Re) and $645.2 million (National Indemnity).

In each of the two prior years, the group also took down reserves in the aggregate—by $1.2 billion in 2009 and $548 million in 2008, with the totals representing 4.9 and 2.4 combined ratio points.

The last time this group of reinsurers took down reserves for consecutive years was the two-year span from 1997 to 1998—with a 0.3 point takedown in 1997 followed by 5.2 points in 1998.

Between 1999 and 2006, reserve boosts outweighed takedowns for almost every year. The only exception came in 2005, when Munich Re America and General Re each recorded prior-year reserve declines of more than $5 billion each. The reinsurers explained that the unusual results related to loss portfolio transfer agreements with parent or affiliated companies (Munich Re in Germany and Berkshire Hathaway’s National Indemnity in the United States.)

If the 2005 reserve changes for the three U.S. companies involved in these LPTs, then the aggregate reserve change for the year is in line with 2004 and 2006—an aggregate reserve hike adding 4.2 points to the group’s 2005 combined ratio.