Just before Manhattan rents started soaring at the start of the year, Blackstone Group agreed to buy a Frank Gehry-designed apartment tower in the Financial District for $930 million.

Today’s big multifamily buys, however, look different from the high-juice deals of yesterday. Instead of buying older properties with heavy rent-stabilized components and banking on the fix-and-flip model, private equity appears focused on free-market buildings with cash flow.

Blackstone’s purchase of the roughly 900-unit Gehry tower at 8 Spruce Street is the city’s biggest multifamily deal so far this year, and it helped push the market close to a record high.

Manhattan multifamily ...