Jeremy Grantham turns cautiously bullish at 900 on the S&P 500

Finally! On October 10th we can say that, with the S&P at 900, stocks are cheap in the U.S. and cheaper still overseas. We will therefore be steady buyers at these prices. Not necessarily
rapid buyers, in fact probably not, but steady buyers. But we have no illusions. Timing is difficult and is apparently not usually our skill set, although we got desperately and atypically lucky moving rapidly to underweight in emerging equities three months ago. That aside, we play the numbers. And we recognize the real possibilities of severe and typical overruns. We also recognize that the current crisis comes with possibly unique dangers of a global meltdown. We recognize, in short, that we are very probably buying too soon. Caveat emptor.

~ Jeremy Grantham, "Reaping the Whirlwind," GMO Quarterly Letter, October, 2008