The pension plan funding levels at large U.S. firms reached “historically low levels” by the end of 2008 due to sharp declines in pension assets and discount rates, according to consulting firm Watson Wyatt.

Watson Wyatt’s analysis looks at pension data for 450 Fortune 1000 companies and projects their pension funding status for 2008. The results indicate that on an aggregate level, funded status will decline an average of 32 percentage points, from 106 percent in 2007 to 74 percent in 2008, representing a total loss of $445 billion, wiping out a 2007 surplus of $78 billion and leaving these companies with a combined $366 billion deficit on their year-end 2008 financial statements Watson Wyatt says.

“Changes in funded status are wreaking havoc with the projections companies have made,” says Watson Wyatt spokesman Alan Glickstein. “Large and unexpected pension contributions will require companies to divert funds they had earmarked for other business activities into their pension plans precisely when they can least afford it.”