Bill Ackman: I'm more bullish on the markets than David Tepper

Caught up in the stock market turmoil on China concerns, Ackman's Pershing Square Capital, with $19 billion in assets under management, lost 9.2 percent last month, erasing gains for the year. Last month, the activist investor disclosed a 7.5 percent stake in snack and beverage giant Mondelez, worth about $5.5 billion at the time. His failed push to help Valent...