U.S. markets moved lower on Monday after the excitement from two big merger announcements faded and weak economic data took center stage. Pending Home Sales unexpectedly fell in June. The National Association of Realtors reported the index was down 1.1 percent last month. Economists were expecting a gain of 0.5%. U.S. Treasury's are also pulling back. On the deals front, Dollar Tree (DLTR) and Family Dollar (FDO) are higher after announcing Dollar Tree would buy Family Dollar for $8.5 billion. Zillow (Z) is trading lower after after saying it would acquire rival real estate website Trulia (TRLA). Trulia is up about 10 percent. Tyson Foods (TSN) is up more than 4 percent despite missing earnings expectations but outperforming revenue estimates. TheStreet's Susannah Lee has the details from Wall Street.