Christopher DeVocht, a carpenter from Vancouver Island, Canada, says he started out like a lot of day traders. After work, he’d read about trading on forums. His favorite things to trade were options on Tesla Inc. stock.

Then he went on what has to be one of the hottest hot streaks in the history of financial markets, according to a legal filing. At the end of 2019, his account, with the brokerage division of Royal Bank of Canada, was worth C$88,000. Within two years, he’d turned that into C$415 million ($306 million), he says.

Some people would have cashed out. DeVocht didn’t. And when Tesla stock fell in 2022, he lost it all, according to a lawsuit he filed this week against RBC Dominion Securities, RBC Wealth Management and accounting firm Grant Thornton LLP. The filing, which is an initial notice of claim that doesn’t require evidence to be provided at this stage, didn’t include brokerage statements or other proof of his gains or losses.

DeVocht now claims that the advice he received, geared mainly toward minimizing taxes, was negligent and failed to take into account his level of financial sophistication. His Tesla investment strategy involved loans from a Royal Bank margin account.

“RBC considered Mr. DeVocht to be a sophisticated investor,” according to the complaint. “While this was true in respect of his strategies for put and call options in the trading of Tesla shares, RBC failed to appreciate that Mr. DeVocht’s knowledge of investing more generally, of financial planning, and of tax was in fact limited.”

Royal Bank had no immediate comment Friday and hasn’t yet filed a defense in the case. DeVocht’s lawyer, Sean Hern, declined to comment beyond the complaint. Grant Thornton said it doesn’t comment on matters before the court.

“The only statement we can provide at this time is that we’re committed to providing quality services to all our clients in accordance with professional standards,” Grant Thornton said in an emailed statement.

DeVocht was good at trading Tesla shares and options, he said in the lawsuit, but he was in his 20s, struggling with “significant respiratory and other health issues” and had limited understanding of financial issues. When he first went to Royal Bank in July 2020, he wanted a loan so he could move out of his rental apartment and buy a home. At the time, his portfolio was worth about C$26 million “and rising rapidly,” according to the notice of civil claim, filed with the Supreme Court of British Columbia in Vancouver.

He was soon referred to a “coach and coordinator” within the bank who then connected him with an accountant at Grant Thornton, according to the complaint.

The assembled team of professionals advised him to incorporate a company, roll all of his securities into it and conduct trades within the company “with a strategy of accumulating as many Tesla shares as possible and holding them for as long as possible,” DeVocht claims in the lawsuit.

The idea was to convince Canadian tax authorities to view it as an investment holding company, not an active trading business, because he’d pay lower taxes that way, according to the complaint.

This led to an “extreme concentration in Tesla” that came with corresponding risks, DeVocht claims. When the stock soared in 2021, it paid off — his portfolios surged to C$415 million from C$186 million in the span of about eight months that year, according to the lawsuit — before collapsing.

Tesla shares suffered a series of declines and periodic rallies throughout 2022 and DeVocht tried to recoup some of the losses by borrowing C$20 million from the corporation and using it to make shorter-term trades in his personal account. That strategy failed, and the money was lost, he said in the complaint. When Tesla shares saw even steeper declines in October 2022, DeVocht’s corporation had to sell its Tesla holdings to repay loans from a margin account it held with Royal Bank, according to the suit.

DeVocht and his corporation tried to mitigate these losses but, in time, their “securities holdings were worth nothing,” he said in the complaint. If not for the “inadequate advice” DeVocht received, he and his corporation “would have preserved a substantial portion of their wealth and implemented financial planning that would not have resulted in the loss of their entire net worth.”

DeVocht and his corporation are seeking general damages for breach of contract and negligence. His claim also alleges that Royal Bank’s recommendations to make C$25.5 million in charitable donations further eroded a significant chunk of his wealth.

This article was provided by Bloomberg News.