U2 generated some pretty impressive coin from their massive 360 Tour, performing 110 shows and reportedly grossing over $736 million from June 2009 through July 2011. Bono’s personal net worth is about to get even bigger. The sunglasses-sporting singer made a huge investment in Facebook stock three years ago, and after shares of the social media site go public, Bono is expected to become the richest rocker in the world.

In 2009, Elevation Partners, Bono’s equity company, purchased $90 million in Facebook stock. Friday, May 18 marks the start of Facebook’s initial public offering on the Nasdaq Stock Market; it’s believed that his $90 million investment could soon be valued in excess of $1.5 billion.

If so, then Bono would surpass Beatles legend Paul McCartney as the wealthiest rock ‘n’ roll star. In addition to album sales and touring revenues, McCartney’s income also comes from a broad range of music publishing he’s acquired through the years.