Billionaire investor Carl Icahn sold his roughly 2.7 percent stake in Lyft Inc. to investor George Soros ahead of the ride-hailing company’s initial public offering, the Wall Street Journal reported on Wednesday, citing sources.

Jonathan Christodoro, a former managing director of Icahn Capital LP who was on Lyft’s board until last month, connected the activist investor with Soros, which was worth about $550 million at the IPO price, according to the WSJ report.

It was not clear what price Soros paid for the stake, according to the WSJ report.

The exact timing and motivation for Icahn’s move couldn’t be determined, though he had held the stake for roughly four years—a relatively long period for him, the Journal said. The activist investor, who rarely invests in private companies, had been unhappy with Lyft’s plan to use supervoting shares to give its two founders near-majority voting rights, some of the sources told the Journal.

Lyft shares (LYFT)  have been pressured in their first week of trading. After pricing ahead of their expected range and surging 8.7% in their debut Friday, they tumbled 12% Monday and were volatile Tuesday before closing Wednesday’s session up 1.5% at $70. Multiple downbeat analyst reports published after the IPO helped pressure the shares.

Lyft could not be immediately reached for comment.