her necklace, becoming the first Rolex ambassador. To celebrate the feat, Rolex published a full-page advertisement on the front page of the Daily Mail for every issue for a whole month proclaiming the watch's success during the ten-hour-plus swim.[19]
In 1931, Rolex patented a self-winding mechanism called a Perpetual rotor, a semi-circular plate that relies on gravity to move freely. In turn, the Oyster watch became known as the Oyster Perpetual.[19] The invention of the Perpetual rotor by Rolex in 1931 revolutionized the self-winding watch, as watches were previously not allowed to be wound using a semi-circular plate that moved freely with gravity.[20]
Upon the death of his wife in 1944, Wilsdorf established the Hans Wilsdorf Foundation, a private trust, in which he left all of his Rolex shares, ensuring that some of the company's income would go to charity. Wilsdorf died in 1960, and since then the trust has owned and run Rolex SA.[10]
The Hans Wilsdorf Foundation, which privately owns Rolex SA, is a registered Swiss charitable foundation and pays a lower tax rate.[21] In 2011, a spokesman for Rolex declined to provide evidence regarding the amount of charitable donations made by the Wilsdorf Foundation, which brought up several scandals due to the lack of transparency.[21] In Geneva where the company is based, it is said to have gifted, among many things, two housing buildings to social institutions in Geneva.
Rolex SA offers products under the Rolex and Tudor brands. Montres Tudor SA has designed, manufactured and marketed Tudor watches since 6 March 1946.[23] Rolex founder Hans Wilsdorf conceived Tudor to create a product for authorized Rolex dealers to sell that offered the reliability and dependability of a Rolex, but at a lower price.[24] The number of Rolex watches was limited by the rate that they could produce in-house Rolex movements, thus Tudor watches were originally equipped with third-party standard movements supplied by ETA SA while using Rolex-quality cases and bracelets.[25] Since 2015, Tudor has begun to manufacture watches with in-house movements. The first model introduced with an in-house movement was the Tudor North Flag. Following this, updated versions of the Tudor Pelagos and Tudor Heritage Black Bay have also been fitted with an in-house caliber.[25][26]
Tudor watches are marketed and sold in most countries around the world. Montres Tudor SA discontinued sales of Tudor-branded watches in the United States in 2004, but Tudor returned to the United States market in the summer of 2013, and to the UK in 2014.[27][28]