Royal Ammar bin Humaid Al Nuaimi spotted wearing a Patek Philippe

Sheikh Ammar bin Humaid Al Nuaimi, Crown Prince of the Emirate of Ajman and a figure well known within Gulf royal circles for his appreciation of serious horology, was recently photographed wearing what is arguably the most complex production wristwatch Patek Philippe has ever offered to private clients: the Reference 5373P, a platinum grand complication with a left-sided crown.

The Patek Philippe 5373P is built around calibre CHR 29-535 PS QA LU, a manually wound movement that combines four of the most demanding complications in watchmaking within a single mechanism: a split-seconds (rattrapante) chronograph, a perpetual calendar with leap-year indicator, a moon phase display accurate to one day's deviation in approximately 122 years, and a minute repeater that chimes the hours, quarter hours, and minutes on demand. The movement comprises 719 components and was developed over more than a decade before its introduction. The platinum case measures 44.6 mm and is instantly distinguished by its crown at 9 o'clock — a configuration that improves ergonomic access to the winding and setting functions without interrupting the symmetry of the right flank.

From a collector standpoint, the 5373P occupies a category occupied by almost nothing else. Patek Philippe does not publish production numbers for special-order references, but market consensus places total output in the single digits to low double digits globally. The piece is not catalogued in the standard collection; it is acquired through a direct relationship with the manufacture, typically by clients with an established acquisition history. Its combination of complications places it in the same conversation as the Calibre 89 and the Grandmaster Chime 6300 — references that define the outer boundary of what the maison will produce for private wrists.

Sheikh Ammar's appearance with the 5373P is consistent with his public profile as a collector of serious mechanical watches rather than merely decorative pieces. The choice of a left-crown grand complication — a detail meaningful only to those who understand the reference — signals horological knowledge rather than conspicuous display.

On the secondary market, the Patek Philippe 5373P commands approximately $500,000 USD, reflecting both its technical complexity and extreme scarcity. No official retail price has ever been publicly confirmed by Patek Philippe, as the reference is handled exclusively on a private-client basis, making grey-market transactions the only available pricing benchmark.