Patek Philippe Perpetual Calendar (Platinum Anniversary)

About this reference

The Patek Philippe Reference 3940 was produced from 1985 to approximately 2007, serving as the brand's flagship perpetual calendar for over two decades. Collectors prioritize this reference for its ultra-thin 36mm case and the Caliber 240 Q, a self-winding movement featuring an off-center 22k gold micro-rotor. The platinum 3940P variant is distinguished by its solid case back and a small diamond set between the lugs at 6 o’clock, a hallmark of the metal. The dial layout utilizes three sub-dials to display the day, month, leap year, 24-hour cycle, and moon phase. On the secondary market, the 3940P typically trades between $65,000 and $95,000 depending on the series and provenance. A notable production detail includes the transition from the early "sunken" sub-dials of the first series to the flatter registers found in later iterations, which significantly impacts individual valuation.