Big investors are pouring unprecedented amounts of money into real estate hard hit by the housing crash, bringing those moribund markets back to life but raising the prospect of another Wall Street-fueled bubble that won’t be sustainable.

Drawn by the prospect of double-figure profit margins on rents and the resale of homes whose prices plummeted in the crash, hedge funds, Wall Street investors and other institutions are crowding out individual home buyers.

If the chain of easy credit and dangerous leverage that started on Wall Street fanned the housing bubble and eventual crash, some analysts find it disturbing that major investors are the ones snapping up the bargains — and eventual big profits — left in its wake.

“There is the possibility that Wall Street and the banks and the affluent 1 percent stand to gain the most from this,” said Jack McCabe, a real estate consultant based in Deerfield Beach, Fla. “Meanwhile, lower-income Americans will lose their opportunity for the American Dream of building wealth through owning a home.”

Real estate executives say institutional investors — who in some cases are bidding on hundreds of homes a day — account for as much as 70 percent of sales in some Florida markets. Over the past two years, analysts say, they also have accounted for a majority of purchases in other parts of the country where housing prices are rebounding sharply.