Zenith SA is a Swiss luxury watchmaker. The company was started in 1865 by Georges Favre-Jacot at the age of 22, in Le Locle in the canton of Neuchâtel. Zenith was purchased by LVMH in November 1999, becoming one of several brands in their watch and jewellery division. Jean-Claude Biver became Interim CEO in 2017, replaced CEO Aldo Magada, who replaced Jean-Frédéric Dufour in 2014.

Zenith has a long reputation for the quality and precision of their watches. It is one of the Swiss watch manufacturers that still produce their own movements in-house.

The El Primero calibre, which was first released in 1969, and still produced today, was one of the first automatic chronograph movements and has a frequency of 36,000 alternations per hour (5 Hz). This high rate allows a resolution of  1⁄10 of a second and a potential for greater positional accuracy over the more common standard frequency of 28,800 alternations per hour (4 Hz). The El Primero was honoured with a 2012 release of the El Primero Stratos Flyback Striking 10th, limited to 1,969 pieces (in honour of the original 1969 release date), that housed the same 36,000 vph movement and a sub-dial measuring in tenths of a second to make a complete rotation every ten seconds.