A $39.5 Million Penthouse at 740 Park Avenue

After serving in top executive roles at places like Goldman Sachs, the New York Stock Exchange and Merrill Lynch, John A. Thain is now ready to make another big move.

He and his wife, Carmen M. Thain, are selling their duplex penthouse at the venerable 740 Park Avenue co-op building, at East 71st Street, which they had been using as a pied-à-terre for the last several years.

The asking price is $39.5 million, according to the listing broker, John Burger of Brown Harris Stevens, with monthly maintenance of $19,215.

“We love the apartment — it is wonderful and also irreplaceable — but we find that we’re just not spending any time there lately,” said Mr. Thain, who described himself as retired after stepping down in 2016 as chief executive and chairman of the CIT Group, the finance company he ran after leaving Merrill Lynch.

He now serves on the board of directors of Uber in San Francisco, and is expected to join the supervisory board of Deutsche Bank in May.

He and Ms. Thain say they are looking to spend more time in California, where most of their children and grandchildren are living. They already have a beachfront townhouse in Santa Monica, in addition to their main residence in Rye, N.Y.

The couple bought their penthouse, which is on the 17th and 18th floors of the limestone-clad 740 Park, for $27.5 million in 2006. They purchased it from the estate of Enid A. Haupt, a noted philanthropist and passionate supporter of the New York Botanical Garden, several months after her death. Ms. Haupt, who was a daughter of the publishing magnate Moses L. Annenberg, had moved into the apartment in 1967.

Long regarded as one of New York City’s most prestigious addresses, 740 Park has housed many other wealthy and powerful residents, from John D. Rockefeller Jr., to more recently, the Blackstone Group founder Stephen A. Schwarzman and the billionaire businessman David H. Koch. (Not surprisingly, financing is not permitted for purchases there.) The building was designed in the late 1920s by the architect Rosario Candela and developed by James T. Lee, a grandfather of Jacqueline Kennedy Onassis, who also lived there.

The Thains said they spent two years making numerous improvements and upgrades to their penthouse, in collaboration with the architect Oscar Shamamian and the interior designer Michael S. Smith. Their work included refurbishing the elaborate architectural finishes (and adding a few of their own), renovating the kitchen and bathrooms, and reinstalling stairs to the roof. They also added a Crestron home automation system.

“It appeared to have been abandoned for a number of years,” Mr. Thain said, describing the apartment’s previous condition. “Fireplaces were closed up and even the roof-level terrace space was completely shut off.”

“I think the previous owner had been wary of intruders,” Ms. Thain added.

The unit’s early-20th century charm has since been restored. Throughout the home — filled with an eclectic mix of antiques, traditional furnishings and striking artwork — are ornate plaster and wood moldings, Parquet de Versailles hardwood floors, functioning wood-burning fireplaces, French doors and oversize windows. Ceilings on the main level reach 12 feet.

“It’s a very elegant apartment,” Mr. Burger said. “You just don’t see these kinds of opulent details anymore.”

The apartment has three bedrooms and three and a half baths, plus an office that could be converted into a fourth bedroom. There is ample outdoor space — with two terraces on the lower level, a wraparound terrace on the top floor and the recreated roof deck — that provide stunning cityscape and Central Park vistas.

“That’s the best part of this side of 740 Park: You have park views,” Mr. Burger said of the building’s west wing, where the penthouse is situated. “The light here is just fantastic.”

On the home’s main level, a private elevator landing opens to a stately windowed gallery 27 feet long, with a grand elliptical staircase and entry to a 15-by-14-foot west-facing terrace. The gallery leads to an enormous living room that also connects to the terrace. It is anchored by a richly carved marble fireplace, one of three in the apartment, and flows into the formal dining room.

Off the dining room is a butler’s pantry with two dishwashers, and beyond that, a large eat-in kitchen with custom marble flooring and a spacious pantry and laundry area. The kitchen is equipped with stainless-steel appliances like a Wolf stove and Sub-Zero refrigerator and wine cooler and also features a stainless-steel center island.

The most eye-catching features in the kitchen are the geometric plaster medallions along the ceiling perimeter — a design idea of Ms. Thain, who wanted to replicate the ornamental details found at the top of the building’s facade.

The apartment’s main floor also contains a small bedroom and an office, both of which share a bathroom, as well as a powder room and a library. The 16-by-19-foot library, lined with sumptuous wood paneling by Féau & Cie of Paris, has a fireplace and French doors that open to a small south-facing terrace.

On the second floor is another spacious gallery, along with a sizable master bedroom with walk-in closets and a fireplace, and a guest bedroom currently being used as a study. Each bedroom has an en-suite marble bath. The master bath features heated floors and a separate soaking tub. Both bedrooms open to the wraparound terrace, with eating and lounging areas.

This floor is reachable via the main staircase and service stairs off the kitchen, as well as a private elevator bank off the gallery. A third set of stairs from this floor connects to the teak roof deck, with trellis walls and various plantings like climbing hydrangea.

Mr. Thain said the roof deck was one of his favorite spots in the penthouse, and one that he will miss the most. “It’s a beautiful space, and it has amazing views.”