STLtoday.comWall Street opens lower as bond yields, Walmart worries weighSTLtoday.comFILE- In this Oct. 2, 2014, file photo, the Wall Street subway stop on Broadway, in New York's Financial District. The U.S. stock market opens at 9:30 a.m. EST on Friday, Feb. 16, 2018. (AP Photo/Richard Drew, File). The Associated Press.