Watchmaker Maximilian Büsser spotted wearing a MB&F

There is something quietly definitive about a watchmaker photographed wearing his own most ambitious creation. Maximilian Büsser, founder of Geneva-based independent manufacture MB&F, is seen here with the HM4 Thunderbolt strapped to his wrist — a watch that, more than almost any other in the brand's catalog, embodies the fearless design philosophy he built the company around when he left Harry Winston Rare Timepieces in 2005.

The HM4 Thunderbolt debuted in 2010 and immediately rewrote what a wristwatch case could look like. The architecture takes its inspiration from twin-engine fighter aircraft of the 1940s — most obviously the Republic P-47 Thunderbolt — with two separate titanium nacelles housing the twin mainspring barrels, interconnected by a central structural bridge. The time display sits in the center pod, read via a battle-proven domed sapphire crystal, while a secondary sapphire window on the right nacelle exposes the movement's beating heart. The manually wound movement delivers approximately 72 hours of power reserve, with hours and minutes indicated via a classic two-hand layout that feels almost understated given the surrounding architecture.

For collectors of independent horology, the HM4 occupies a genuinely important position. It marked MB&F's full maturity as a design force — moving beyond the disc-and-dome aesthetic of HM1 and HM2 into fully volumetric, sculptural case engineering. Produced in titanium, white gold, and a small number of special editions, total production across all variants is believed to be well under 200 pieces, cementing its status as a serious rarity rather than a boutique curiosity.

Büsser founded MB&F — Maximilian Büsser & Friends — on a collaborative model, partnering with independent movement makers, designers, and engineers on each new Horological Machine. The HM4 was developed in close collaboration with movement specialist Jean-Marc Wiederrecht of Agenhor. That Büsser wears this piece in an official portrait setting rather than a dress watch says everything about how he views the brand's identity.

On the secondary market, the HM4 Thunderbolt in titanium consistently commands premiums above original retail, with clean examples in full set regularly trading between $120,000 and $160,000 depending on variant and provenance. The white gold versions fetch considerably more. For a watch that retailed at approximately $160,000 at launch, that retention is a mark of genuine collector respect.