U.S. stocks extended losses as poor earnings from Gilead Sciences (GILD) - Get Report dragged the entire health care sector lower. Markets were also down after a monthly reading on consumer activity in the U.S. showed a tendency to save instead of spend. Consumer sentiment fell in April as Americans grew more concerned over future economic conditions. This marks the fourth straight monthly decline. Economic activity in the Chicago area weakened in April as a softer global economy tempered demand for U.S. products. The Chicago PMI was just above the level that separates expansion from contraction. Rovi (ROVI) announced that it had reached an agreement to buy Tivo (TIVO) - Get Report for around $1.1 billion in a cash-and-stock deal. The companies expect annual cost synergies of at least $100 million. TheStreet's Keris Lahiff reports from Wall Street.