Bill Ackman's Pershing Square slashes stake in Chipotle, continues to bet on Nike

1. Bill Ackman increased Nike stake by 15% while reducing Chipotle stake by 14%. 2. Pershing Square owned 24.7 million shares in Chipotle, down from 28.8 million. 3. Ackman's firm moved from aggressive activism to a quieter investment strategy. 4. Chipotle, previously a big winner, sees reduced confidence from Ackman's firm. 5. Regulatory 13F filing reflects changing investment strategies in prominent stocks.