DO the buyers of Starrett City have something up their sleeve? Local real-estate experts don’t see how the new owners – who paid $1.3 billion, hundreds of millions above the No. 2 bid – can make money on the deal. So some suspect the plan is to get a new round of government subsidies for the project.

Politicians like Sen. Charles Schumer are mobilizing big-time against the sale, saying the city can’t afford to lose the huge project’s state-financed and federally subsidized affordable apartments. Notably, state Attorney General Andrew Cuomo is seeking to enforce a ban on David Bistricer (the head of the investor group) – the state Supreme Court him put under a permanent injunction in 1998 from buying or offering co-op buildings.

Urban planners have long seen Starrett City – the largest federally subsidized rental property in the country – as a monument to questionable government judgment. The immense, barracks-style project is in East New York, Brooklyn, a good 90-minute subway ride from Manhattan jobs. At about $220,000 per unit, the buyers have paid handsomely for the 5,881 apartments in 46 buildings, housing some 14,000 people on 140 acres.

Now it’s private-sector judgment that looks dubious. Dick Netzer, emeritus professor of economics at NYU, calls the deal “mystifying.”

Those who compare this sale to that of Manhattan’s Stuyvesant Town are wrong. Not only is Starrett’s location lousy, to use Netzer’s word, but it’s gotten so many government subsidies over the years that federal and state housing officials must OK the sale – and not one of them has spoken out publicly in its favor.

Originally envisaged by the labor movement as a way to house middle-income union members within city boundaries, Starrett fell from fashion before it even opened back in 1974. Workers with savings to invest preferred to put their nest eggs into single-family suburban homes, the rather than in austere urban high-rises.

The lead union financier, United Housing Foundation, walked away, selling its interest to the Starrett Corp., which finished it under the state Mitchell-Lama program as subsidized middle-income housing.

Even though the project was built on landfill next to a garbage dump, Starrett managed to make it relatively attractive, adding such amenities as a community center and swimming pool, and maintained the landscaped grounds beautifully over the years. “The old management did an honest job of running the project well,” says Netzer. “They kept tenants satisfied. In New York, if there’s any significant number of people dissatisfied you know about it: They shout it from the roof tops.”

But the project basically provides plain apartments in severe towers – not anything like luxury housing. So market-rate rents likely wouldn’t be much higher than current rents – certainly not the thousands of dollars per month higher that Stuy Town’s new owners can anticipate.

Jerilyn Perine, executive director of the Citizens Housing & Planning Council, notes, “Even if you make every aggressive assumption you can on the rental side, and even if you had empty buildings, which you don’t, you’re unlikely to get that rent above $1,900 a month.”

The only answer lies elsewhere, with what Perine calls a “new-build component” – putting up new towers among the existing ones. The current towers occupy less than 20 percent of the acreage, leaving plenty of room for new development.

But development for whom? That’s where new government subsidy might come in.

Real-estate consultant Robert C. Rosenberg, who managed Starrett for many years as head of Grenadier Realty, says he could imagine the new owners deciding to market new multibedroom units to large Orthodox families being squeezed out of Williamsburg. Says Rosenberg, “They might not want to get rid of Section 8. They might want subsidies for these new families.”

One thing is clear: However Bistricer and his partners intend to turn a profit, they won’t be doing so soon. Comments Rosenberg: “On the numbers, this deal doesn’t make a lot of sense. As a guy who teaches a graduate course in real-estate economics, I’d have to say this isn’t one I would recommend.”

In other words, it just doesn’t add up.

Julia Vitullo-Martin is a senior fellow at the Manhattan Institute.