In Los Angeles, for example, the home prices to incomes ratio is now 26 percent higher than it was 13 years ago, the Los Angeles Times reported Friday.
In addition, "so many people in LA are in between where they bought at huge bubble prices in 2005 and 2006 and now, and they are not willing to list their homes," Redfin Chief Executive Officer Glenn Kelman said.
In theory, home prices rising faster than incomes creates an opportunity for prices to collapse, because at some point prices have gone too far ahead of the ability for people to afford a home.
For now, "The result is there is a rush on what inventory is out there," Kelman said.
Redfin said 91 percent of the homes it sold in March involved a bidding war, the newspaper said.
Los Angeles came in behind Washington as the second most bubble-like market, the Times said.
In a study of 15 cities, the least bubble-like markets are in Atlanta and Chicago, the report said.