The hedge fund manager said his fund began buying Uber shares in early January and has amassed 30.3 million shares, worth $2.3 billion.

Uber’s stock extends its surge as hedge funder Ackman says he’s amassed a 30.3-million-share stake since early January.

Billionaire hedge fund manager Bill Ackman revealed on Friday that his activist investment firm has bought up approximately $2 billion worth of shares of Uber — sending the ride-share company’s stock surging.