The S&P 500 slipped 0.4% and is on track for a third straight modest loss after setting its all-time high last week. The Dow Jones Industrial Average was up 8 points, or less than 0.1%, as of 11:50 a.m. Eastern time, and the Nasdaq composite was down 1%.

Shares of leading designer of graphics chips Nvidia (NASDAQ:NVDA) fell 3.5% in the afternoon session after investors took some profits off the table as markets awaited signals on future monetary policy from the Federal Reserve's Jackson Hole symposium later in the week.