If Goldman Sachs (NYSE: GS) is correct, that is exactly what's in store for us. On Monday, the investment bank raised its end-of-year forecast for the S&P 500 from 940 to 1,060. The new target implies a 15% gain in the second half, which would be the best second-half performance since 1982. That sounds looks like a strong signal to load up on stocks.

Not so fast
How did Goldman come up with this new target? For one thing, they've raised their earnings estimates for the S&P 500 substantially:

2009e

2010e

S&P 500 Earnings (increase over previous estimate)

$52

(+30%)

$75

(+19%)

S&P 500 P/E Ratio , based on closing price on July 21 Continued...