Bill Ackman just made Uber his largest position at Pershing Square. It now makes up 12.7% of his $19 billion portfolio. The stock is down about 31% from its 52-week high and is trading at a 16.2 forward P/E. His firm projects Uber's EPS will grow around 25% annually over the next 3 to 5 years, driven by user growth and higher order frequency. The main risk dragging the stock down seems to be autonomous vehicles like Waymo and Tesla's Robotaxi. However, AVs currently account for just 0.1% of global rides. Waymo does about 500k rides a week compared to Uber's 297 million. Ackman's thesis is that AV adoption will take time, and even if it scales, Uber is positioned to act as a demand aggregator that bundles these different fleets together.