U.S. stocks are opening lower as investors worry about some soft economic data from China and a profit warning by the British retailer Tesco.

The Dow Jones industrial average fell 19 points, or 0.1 percent, to 17,259 as of 9:35 a.m. Eastern time Monday.

The Standard & Poor's 500 index fell three points, or 0.2 percent, to 2,007. The Nasdaq composite lost 12 points, or 0.3 percent, to 4,565.

The Dow had three record-high closes last week and is coming off of five straight gains.

Yahoo fell 3 percent, the most in the S&P 500.

Sigma-Aldrich rose the most, 34 percent. The St. Louis-based chemical firm agreed to be bought by the German drug company Merck.

Bond prices rose. The yield on the 10-year Treasury note fell to 2.57 percent.