Now these REITs must figure out how to earn an adequate return on their investments in a housing market that has seen significant changes over the past year.
"Five years ago, the yields were so good, you could still make a lot of money even if your management costs were high," said Richard Green, director of the USC Lusk Center for Real Estate.
The yields aren't as good now, he says. That puts more pressure on REITs and other investment companies to boost yields through more efficient management.
For smaller local operations, management is not that difficult because people are nearby to handle property issues immediately.
It's a tougher job for large, national-scale companies that are headquartered hundreds or even thousands of miles away from the homes that they own.
"Arguably when you get scale, you can hire your own plumbers and electricians, and maybe help costs go a little lower that way," Green said. "But it's still a mystery to me how they can manage the properties efficiently enough and get the right yields under this business model."