Audemars Piguet Royal Oak Skeletonized Perpetual Calendar

About this reference

Produced between approximately 1986 and the mid-1990s, the Audemars Piguet Royal Oak Perpetual Calendar Openworked reference 25636BA is a significant neo-vintage reference housed in a 39mm 18k yellow gold case. Collectors prioritize this model for its ultra-thin self-winding caliber 2120/2800, which lacks a leap year indicator, a characteristic of early perpetual calendar movements. The sapphire dial reveals the hand-finished skeletonized components, while the absence of a sapphire caseback on many early examples distinguishes it from later iterations. Total production for the 25636BA is estimated at 126 units, making it rarer than its non-skeletonized counterparts. On the secondary market, prices typically occupy the mid-to-high six-figure range, depending on the presence of the original box and papers. A notable auction result occurred in 2022 when a well-preserved example sold for over $400,000, reflecting the high demand for early openworked Royal Oaks.