Here's an incredible stat from DataQuick: the rate of flipping activity in California hit an all-time high in February and remains well above pre-recession levels.
In May, Southern California's rate hit 5.9%, the Bay Area notched 4.1% and the state averaged 5.3%.
The boom peak for all three was about 4.3%, reached in January 2005.
The rate reflects the percentage of properties on the market that were previously sold within the past six months.
Here's the chart:

chart_1 (4)
DataQuick

DataQuick's Andrew LePage told us the spikes stem from aggressive investors who survived the crash mopping up on low, low prices:
Investor purchases are at or near record levels — there's just a lot more investment activity. What we didn't have back in the boom times was heavily discounted foreclosed properties...That's what these flippers have been feeding on.