Trump suffered a particularly rough patch in the early 1990s, when the value of his holdings fell far below their heavy debt load, forcing him to hand properties over to his lenders. In those dark days, The Donald frequently walked from his offices to lunch nearby at one of his troubled trophy properties, the Plaza Hotel. Many times, he’d invite his top financial specialist, who was then leading thorny negotiations with the banks, to join him. As the finance man tells the story, one day en route to the Plaza, Donald pointed to a homeless person sitting on a cardboard box and quipped, “That guy isn’t worth 10 cents, but he’s got $900 million more than me!”

Today, Trump is benefiting immensely from the soaring prices of New York real estate. Over the past weekend, his privately owned development and brokerage firm, The Trump Organization, announced a sale that underscores the strength of the Manhattan luxury market: $21 million for an apartment in a building Trump transformed from an aging hotel into one of the Upper East Side’s top residential addresses.

In 2002, Trump bought the 1929 Hotel Delmonico, and converted the 35-story building into 119 apartments. Fortune spoke with his daughter Ivanka, who heads development and acquisitions for the Trump Organization (and lives in the building in question), about her father’s strategy. “My father sold most of the units, but he also held back a number of apartments, and rented them,” says Ivanka. “Two of the units brought the first and second highest rental prices in Manhattan, over $100,000 a month.” The apartment that just sold, she adds, had been leased “north of $85,000 a month,” and that the tenants recently departed, making the unit available for sale. “The building sold incredibly well,” she says, “but we have no mortgage, and we’re believers in New York property values. That’s why we held back some units.”

The apartment—Penthouse 24—covers almost 6,200 square feet, boasting five bedrooms and seven-and-a-half baths, not to mention a private elevator. The online video advertising the unit incorporates the kind of verbal bravado Trump is famous for, extolling the “sprawling oasis” that’s “idyllically situated.” The furnishings, not included in the price, demonstrate the preferred Trump staging: ultra-modern décor orchestrated to lend the highest of high glosses to his top offerings. Visitors trod over zebra rugs and around avant-garde abstract brass sculptures.

An even more expensive unit, also owned by Trump, is on the market for the first time. It’s Penthouse 31-32, a duplex featuring about the same interior space as Penthouse 24 and flanked by 2,000 square feet of terraces, a major attraction for the super-rich who covet rare outdoor space. Asking price: $35 million.

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Given that Ivanka’s dad is her boss and no one is more familiar with his management style, Fortune asked her what kind of president he’d make. “I think he’s exceptional in all he does, and that would be true of his presidency,” she said. “I’m his biggest advocate and he’s an absolute inspiration to me.”

In real estate, The Donald’s instincts are quicksilver, as this big sale demonstrates. We’ll soon see if he reads the voting public as skillfully as he foresees real estate trends.