Pop open the case back of any Swiss mechanical timepiece—particularly those from the entry-level or mid-range category—and there’s a high chance that the movement is not made by the same company that made the watch.
The oscillating rotor or mainplate may be decorated with the brand’s insignia, but the movement is very likely made externally by one of these three companies: ETA, Sellita, or Soprod. Producing anywhere from a few hundred thousand to several million movements a year, these pillars of the watch world virtually carry the weight of the industry on their shoulders.
Founded in 1856 by the Eterna watch company, ETA is the oldest and biggest movement supplier on the market today. Owned by the Swatch Group and headquartered in Grenchen, Switzerland, it started life as a division at Eterna SA, specialising in movement production. Over the decades, it supplied Eterna, as well as numerous other watch companies with fully assembled movements, and also ébauches, which are sets of movements that have not been assembled.
Of the 32 mechanical calibres it currently produces, ETA’s Calibre 2892A2 is widely regarded as the finest, most versatile, and reliable self-winding movement for its price (approximately CHF280). This bestseller is tolerably slim at 3.6mm, with a modest diameter of 25.6mm, making it an ideal base on which to stack additional modules.
ETA supplies three grades of Calibre 2892A2: elaborated, top, and chronometer. The maximum daily variation ranges from +/- 20 seconds a day for the elaborated grade movements, to +/- 15 seconds a day for top grade ones. Chronometer grade ones adhere to COSC’s standards, a maximum of +/- 5 seconds a day.
Established in 1950, Sellita started out assembling the Calibre 2824 for ETA, but set out making its own movements in 2003. As of 2013, its annual production has reached 1.4 million units, making the La Chaux-de-Fonds manufacture the closest thing ETA has to a rival—though nowhere close to ETA’s output of five to six million per year.
Of its five movement families, Sellita’s SW300 line has proven most popular with the luxury segment. SW300 is essentially a clone of ETA’s Calibre 2892A2, with the exception of an additional jewel on the barrel axis to reduce friction.
Literally no different from the ETA equivalent, SW300 is thus the most viable alternative for brands like Bell & Ross, IWC, Baume & Mercier, Zenith, Montblanc, TAG Heuer, Sinn, Franck Muller, and more. Based on a 2014 report by Europa Star, Sellita supplies to around 250 brands.
Like Sellita, Soprod had also been a sub-contractor of ETA for a time but this Tramelan-based firm boasts a much wider manufacturing scope. For starters, Soprod has been making its own movements since its founding in the 1960s.
Soprod belongs to the Swiss Festina Group, which also owns Manufacture Horlogère Vallée de Joux in Le Sentier and Manufacture des Spiraux et Echappements in Muriaux, firms that supply Soprod with key regulatory components like the escapement and spiral. Therefore, unlike other movement makers, including Sellita who rely heavily on the Swatch Group-owned Nivarox for escapements and balance springs, Soprod has the ability to source its own, and this speaks volumes about its in-house manufacturing capabilities.
As of 2013, its annual production stands at a modest 100,000 movements, which is a far cry from Sellita’s numbers, but Soprod is decidedly more independent—it makes every component of its Calibre A10 with the exception of the jewels, barrel spring, and shock absorbers. Apart from the position of the balance cock and the design of the regulator, Calibre A10 is largely similar to the ETA and Sellita calibres.