Just over a month ago, Patek Philippe unveiled its celebratory timepieces in honor of the company’s 175 birthday. As part of the announcement, Hodinkee editor Benjamin Clymer noted that the legacy brand would be auctioning off its Henry Graves Supercomplication watch for only the second time in the brand’s storied history. The most expensive watch in the world was auctioned off just one other time. It sold for $11 million, shattering every auction sale in history.

The watch was, up until recently owned privately by the Qatari Royal Family, but on November 11, the world’s most valuable timepiece was slated for auction again. And this time, the price tag just went up — to more than $15 million. On sale in Geneva, Sotheby’s noted that the Supercomplication is, “A gold, double-dialed and double open-faced, minute repeating clockwatch with Westminster chimes, grande and petite sonnerie, split seconds chronograph, registers for 60-minute and 12-hours, perpetual calendar, moon-phases, equation of time, dual power reserve for striking and going trains, mean and sidereal time, central alarm, indications for times of sunrise/sunset and a celestial chart for the night time sky of New York City.”

And on November 12, the watch sold for an unprecedented $24 million. While no one knows who the watch sold to, the bid was made via Aurel Bacs, the director of Christie’s and head of Phillips Watches, who placed the bid through his iPhone.