This article in today's Sac Bee talks about how small investors are buying up foreclosures. It notes that the investor share of home purchases in Sacramento County is now up to 28%, compared to 18% a year ago. The article notes the last time investor share exceeded 25% was in 2004-05.
I actually think it's a little surprising (and positive) that the investor share isn't even higher. Folks are worried about their neighborhoods converting into rentals, but the rate is no higher than during the boom. The difference is the fear vs. optimism about the market. I bet that a large share of the foreclosure properties currently selling were originally owned by investors too - so it may not be true that this indicates that the rental share is increasing a lot.
I suspect the current investor % would be much higher if financing were more available, and would be interested in seeing the change between cash investment buyers over time.
The hidden part of the story is that there are lots of renters out there who didn't buy with exotic loans when prices went extremely high. Those people are buying more homes now too (at affordable prices), not just investors. That is very good news.
I don't have the exact data - but the back of my envelope estimates the Sacramento County numbers as: Total Sales Increase by 826 between Jan 2008 and 2009. Of this increase, owner occupant sales increased by 487 (from 883 to 1370) and investors increased by 339 (from 194 to 533). So, in absolute terms the increase in owner-occupant buyers has been larger than investors, but in % terms the growth in invesment buyers is much larger and could be seen as a sign of prices near a bottom.