U.S. stocks open mostly down, with S&P 500 struggling to snap back-to-back weekly losses

U.S. stocks opened mostly down Monday, with the S&P 500 drifting lower after back-to-back weekly losses in a quiet day on the economic calendar. The Dow Jones Industrial Average
DJIA,
-0.03%
was flat soon after the opening bell, while the S&P 500
SPX,
+0.19%
slipped 0.2% and the Nasdaq Composite
COMP,
+0.31%
slid 0.4%, according to FactSet data, at last check. Last week the S&P 500 fell 0.3%, in a second straight weekly decline that brought the index’s losses so far this month to 2.7%, according to Dow Jones Market Data.