Hedge funds and REITs are not involved in single family residential in the Bay Area, and even as a whole they are small players. Most REIT assets by far are in commercial / multifamily property.
They're huge players in single family rentals. Blackstone (a hedge fund) is the largest owner of single family rentals in the USA. And they really don't care about cash flow that much, they are trying to inflate the price of the asset, hence all the "cash over asking" sales. Which means they will dump it when they can't keep causing the prices to rise.