The Brant Foundation Art Study Center — a picturesque gallery space inside a converted 1902 stone barn — is just down the road from the Greenwich, Conn., estate of its creator, Peter M. Brant, the newsprint magnate and avid art collector. There are no identifying signs for the center, whether at the turnoff on North Street, at the security gate or on the building itself, though the location is known to the art-world cognoscenti and celebrities who attend the twice-a-year gala openings, held at the private polo club next door that Mr. Brant also founded. Visits to the center itself are by appointment only.

Mr. Brant’s five-year-old museum, cloistered as it is, nonetheless is the beneficiary of what is in effect a federal subsidy. Operated by a nonprofit charitable foundation created and controlled by Mr. Brant, this cozy museum is tax-exempt.

Wealthy collectors, of course, have long saved millions of dollars in federal taxes by donating art and money to museums and foundations. But what distinguishes Mr. Brant’s center and a growing number of private tax-exempt exhibition spaces like it is that their founders can deduct the full market value of any art, cash and stocks they donate, even when the museums are just a quick stroll from their living rooms.