Elon Musk’s year of dizzying ascents hit a new apex Monday as the Tesla Inc. co-founder passed Bill Gates to become the world’s second-richest person.

The 49-year-old entrepreneur’s net worth soared $7.2 billion to $127.9 billion, driven by yet another surge in Tesla’s share price. Musk has added $100.3 billion to his net worth this year, the most of anyone on the Bloomberg Billionaires Index, a ranking of the world’s 500 richest people. In January he ranked 35th.

His advance up the wealth ranks has been driven largely by Tesla, whose market value is approaching $500 billion. About three-quarters of his net worth is comprised of Tesla shares, which are valued more than four times as much as his stake in Space Exploration Technologies Corp., or SpaceX.

Musk’s milestone marks only the second time in the index’s eight-year history that Microsoft Corp. co-founder Gates has ranked lower than number two. He held the top spot for years before being bumped by Amazon.com Inc. founder Jeff Bezos in 2017. Gates’s net worth of $127.7 billion would be much higher had he not donated so prodigiously to charity over the years. He has given more than $27 billion to his namesake foundation since 2006.

With Monday’s move, Musk unseats an occasional verbal sparring partner in Gates, who the Tesla billionaire has ridiculed on Twitter for, among other things, having “no clue” about electric trucks. The two have also traded barbs over Covid-19. Gates, whose charitable foundation is one of the preeminent bodies backing vaccine research, has expressed concern over Musk’s stated suspicion of pandemic data and embrace of certain conspiracy theories.

The year has been a lucrative one for the world’s richest people. Despite the pandemic and widespread layoffs that have disproportionately affected the world’s working class and poor, the members of the Bloomberg index have collectively gained 23% — or $1.3 trillion — since the year began.