Tesla and SpaceX leader Elon Musk came close to doubling his net worth in 2021, adding to the enormous fortune that has made him the world’s richest person.

Musk started the year with a net worth of $156 billion and ended it worth $277 billion, according to the Bloomberg Billionaires Index.

The $121 billion gain in net worth was a 78% increase of his personal fortune. Musk had an even larger gain in 2020, when he added $140 billion to his net worth.

Musk, who has recently moved his primary residence to Texas and relocated Tesla’s corporate headquarters to Austin, said he expects to pay more than $11 billion in taxes for 2021.

The 10 richest people in the world added a combined $402 billion to their fortunes in 2021, according to the Bloomberg Billionaires Index, with Musk’s $277 billion net worth by far the largest fortune.

Musk’s closest competitor, Amazon founder Jeff Bezos, will enter 2022 worth $190 billion. That’s a $4.5 billion gain since this time last year.

Facebook founder Mark Zuckerberg added nearly $25 billion to his fortune in 2020. He’s worth $128 billion, according to Bloomberg.

Microsoft founder Bill Gates began the new year worth $139 billion. He entered 2021 with a value of $132 billion. His former wife, Melinda French Gates — who ended her 27 year marriage to Bill in August — reportedly has a net worth of $11.4 billion.

Google co-founder Larry Page cracked the 12-digit club in 2021 by adding $47 billion to the $83 billion he had coming into this year. Fellow Google co-founder Sergey Brin also enjoyed that distinction by becoming worth $125 billion, thanks to a 2021 gain of $45 billion.