You made me curious enough to look up the history:
Founded by Chris Sheldrick, Jack Waley-Cohen, Mohan Ganesalingam, and Michael Dent, what3words was launched in July 2013. Sheldrick and Ganesalingam originally conceived the idea after Sheldrick struggled to get equipment and bands to event locations on time due to inadequate address information while working as a concert organiser. The company was incorporated in March 2013 and a patent application for the core technology filed in April 2013.
In November 2013, what3words raised US$500,000 of seed funding; in March 2014 it raised a second seed round of US$1 million; in November 2015, it completed a US$3.5 million Series A funding round; and in June 2016, it completed a US$8.5 million Series B round.
In January 2018, Mercedes-Benz bought approximately ten per cent of the company and announced what3words support in future versions of the Mercedes-Benz User Experience infotainment and navigation system. The A-Class, launched in May 2018, became the first vehicle in the world with what3words on board.
From Wikipedia: https://en.wikipedia.org/wiki/What3words