Over $600 million in value was attributed to Sam Altman's Reddit stake following its initial public offering on the NYSE.

• On Thursday, Reddit's New York Stock Exchange debut saw OpenAI CEO Sam Altman emerge as a significant victor.
• Altman's stake in Reddit increased by $200 million, making it worth over $613 million after the stock jumped 48%.
• Like other insiders, Altman is restricted from selling shares for six months.

Sam Altman, CEO of OpenAI, states that he holds no equity in the $80 billion AI startup he founded in 2015.

His ownership is another matter altogether.

On Thursday, Reddit's stock market debut, Altman's stake in the social media site increased by $200 million to over $613 million. The 19-year-old company's shares rose 48% in New York Stock Exchange trading, closing at $50.44.

Advance Magazine Publishers and Chinese internet giant are the only other shareholders of Reddit besides Altman, who owns 7.6% of the outstanding shares after the offering.

Altman, like other insiders, is prohibited from selling Reddit shares for six months during the lock-up period. He declined to provide any comment.

Altman, known for his investment in Y Combinator and his portfolio that includes stakes in companies such as OpenAI, Stripe, and others, was previously best recognized as a startup investor.

He was on Reddit's board until around January 2022, when the company announced his departure.

In 2014, Reddit raised $50 million in Series B funding, with Altman leading the round. After using the platform for nine years, he wrote a blog post about how the website had evolved from a time-wasting toy to something much more interesting.

In 2021, Altman invested $60 million in Reddit across two financing rounds, but the investments have not yet yielded significant returns as Reddit's valuation after Thursday's rally is still below its private market peak. According to Reddit's filing, Altman invested $50 million at $42.47 per share and $10 million at $61.79 per share.

However, the money he pumped in a decade ago has multiplied many-fold.

The controversy surrounding Altman's leadership at OpenAI has been overshadowed by the pressure he faced to profit from the company. Last year, the board briefly fired him, citing a loss of confidence in his leadership. However, he was reinstated after intense pressure from employees and investors.

This month, OpenAI announced that Altman would be rejoining its board after an internal investigation by WilmerHale into the circumstances surrounding his removal had been completed.

In a May hearing, Altman informed senators that he is not in his current job for the money. According to filings, he earned a total of $73,500 in compensation in 2022.

"I am compensated for my health insurance and do not have any equity in OpenAI," Altman replied to Sen. John Kennedy, R-La., when asked about his earnings in his job. "I am doing this because I am passionate about it."

— CNBC's Jonathan Vanian and Jordan Novet contributed to this report

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