In Tuesday's installment of Investor Beat, host Chris Hill and Motley Fool analysts Jason Moser and Charly Travers take a look at the biggest investing stories of the day.

Yum! Brands announced that China same-store sales for KFC fell 13% in July. The company blamed concerns over safety violations in China's chicken supply. In our lead story on Investor Beat, Jason and Charly examine how much longer the company can endure these setbacks in China and whether today's drop in the stock price means it's time for investors to buy.

Also, our analysts take a look at four stocks that made big moves on Tuesday's market. The U.S. Department of Justice blocks US Airways' merger with American Airlines. Bill Ackman resigns from the board at J.C. Penney. Orbitz Worldwide takes a hit after one of its largest shareholders sells a big stake. And Avanir Pharmaceuticals partners up with Merck.

Finally, Jason and Charly each pick one stock that they'll be watching closely in the week ahead that investors should be watching, too.