The rout that erased $2.9 trillion from U.S. equities has pushed valuations in the Standard & Poor’s 500 index 25 percent below the average level from the last nine recessions, Bloomberg reported.

Companies in the benchmark gauge for American equities trade at 10.2 times 2012 forecast earnings, compared with the average of 13.7 in economic contractions since 1957, Bloomberg said.

At the same time, analysts have cut projections for profits next year by 2.6 percent to $110.78 a share, the biggest eight-week drop since 2009, the data show.

“What you’re seeing is a growth scare,” said Wayne Lin, a money manager at Baltimore-based Legg Mason Inc. “The question is, how much of that is priced in. I’d say that if we don’t have a double-dip recession, if earnings just stay flat, these valuations are reasonable. The market already expects those downgrades.”

Analysts have slashed forecasts for 2012 earnings to the lowest level since April, according to Bloomberg’s research. Projections have been falling for companies such as  JPMorgan Chase & Co. and Caterpillar Inc. since Standard & Poor’s stripped the United States of its AAA credit rating on Aug. 5.

Analysts underestimated the credit crisis that began in 2007 and cut forecasts throughout 2008 when the economy contracted, Bloomberg said. The reduction in profit estimates didn’t end until May 2009, two months after the benchmark sank to a 12-year low, Bloomberg data show.