Over the past year Tesla CEO Elon Musk has lost over $200 billion, making him the first person in history to lose that much money, according to a Saturday report in Bloomberg which examined calculations from its Billionaire Index.

Musk’s net worth had swelled to $340 billion late last year, as Tesla’s market capitalization surpassed $1 trillion. However the news outlet now calculates his net worth is $137 billion.

Analysts note the majority of the losses are attributable to the poor performance of Tesla stock of late, which has lost 65% for the year, with its slide accelerating after the billionaire CEO undertook his acquisition of social media platform Twitter.

As part of his financing of the acquisition, Musk had been selling shares of his electric vehicle maker, as well as spending the majority of his time at Twitter headquarters, leading investors to accuse him of prioritizing the social media platform over Tesla.

For his part Musk has dismissed concerns over Tesla’s performance, noting the company is “executing better than ever.” In a letter to employees, he noted the stock price has been volatile, but said he still expects Tesla will become the most valuable company in the world with time.

However as Tesla’s stock price declined, Musk already lost his position as the world’s richest man earlier this month when the title passed to French billionaire Bernard Arnault, owner of LVMH.