Stock market today: Dow, S&P 500, Nasdaq moderate as markets digest Warsh's Jackson Hole speech

US stocks moderated from earlier gains in midday trading on Friday as investors digested Kevin Warsh's first keynote address at the annual Jackson Hole Symposium, with the Fed chairman's comments interpreted as mildly hawkish in the near term.The Dow Jones Industrial Average (^DJI) slipped below the flat line, while the S&P 500 (^GSPC) slide 0.2%. The Nasdaq Composite (^IXIC) declined by 0.4% after rising by as much as 0.5% earlier in the day.In his speech, Warsh stated that inflation was running too high and that price stability would be the Fed’s predominant focus. Even if market participants didn't necessarily get all of the clarity they were looking for, Warsh's comments were taken as hawkish enough to send yields on short-term Treasurys higher by several basis points.In the equities market, investors continued to digest Nvidia's (NVDA) blowout earnings report and growth projections from Wednesday, while shares in Marvell Technology (MRVL) fell on its own second quarter figures. PayPal (PYPL) lost more than 10% on the news that Advent and Stripe have backed out of a proposed $50 billion takeover.Upward revisions in the University of Michigan's consumer sentiment readings, released at 10 a.m. ET, provided a lightly positive note for the economy.