According to the Netherlands Financial Markets Authority, Gates purchased the €850m shares on 17 February.
Gates purchased the shares from Mexico's FEMSA, which sold all 18 million of its shares held in Heineken Holding.
In a 2018 interview with Reddit, Gates said: "When I end up at something like a baseball game I drink light beer to get with the vibe of all the other beer drinkers. Sorry to disappoint real beer drinkers,” as the move is a surprise to some.
Heineken was recently ranked first place as the bestselling beer brand in Drinks International’s 2023 Brands Report.