The Pershing Square CEO said he's admired the ridesharing giant since actor Edward Norton introduced him to the app in its early days.

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.

Bill Ackman said his hedge fund Pershing Square Capital Management owns 30.3 million shares of Uber Technologies Inc., citing the strength of the rideshare company’s management and saying that its stock is undervalued.