How a $170 Million Painting Scored Its Buyer Unlimited Frequent Flier Miles

When billionaire art collector Liu Yiqian and his wife, Wang Wei, bought a $170 million Modigliani painting, they charged it to their American Express credit card, acquiring essentially unlimited frequent flier miles for them and their family.

Liu, a former taxi driver turned businessman, won Amedeo Modigliani’s Reclining Nude at a Christie’s auction earlier this month. He paid a record amount paid for a Modigliani painting and the second highest price ever for a painting at auction, beat out only by Picasso’s $179 million Women of Algiers.

Liu and his wife charged the Modigliani to their credit card with a one-year payment plan, the New York Times reports, otherwise the billionaire couple say they wouldn’t be able to afford it.

Wang told the Times that Liu had at one point considered purchasing a private plane. She convinced her husband to instead put that money towards an art museum in Shanghai, and it’s paid off. With their various art purchases, the couple and their extended family of four children and two grandchildren, fly for free.

Liu also charged another objet d’art to his American Express last year—a $36 million ancient Ming Dynasty ceramic teacup, which he had infamously been photographed drinking from. Bloomberg reported at the time that the purchase earned he and his wife 28 million frequent flier miles, enough to literally fly around the world more than 1,000 times.

This article originally appeared on Fortune.com