U.S. stock futures were mixed and Treasury yields rose slightly in early European trade as markets nervously await Federal Reserve Chairman Kevin Warsh's first appearance at the Jackson Hole symposium. Investors are set to hang on Warsh's words for clues to the central bank's rate-setting path following the surprise intervention of Treasury Secretary Scott Bessent to cool longer-dated yields last week and signs of sticky inflation. Jackson Hole has often been the setting for significant interventions by Fed chairs, Deutsche Bank analysts noted.

The address will seek to restore confidence in the Fed's commitment to taming inflation and ease concerns that the absence of forward guidance will undermine stability, Samarra Hammoud, FX strategist at CBA, said. Futures for the Dow Jones Industrial Average rose 0.2%, while S&P 500 futures were flat. Nasdaq futures slipped 0.3%.

Yields on 10-year Treasurys edged up 0.8 basis point to 4.679%. PayPal tumbled 14% after an Advent-linked firm and payment processor Stripe abandoned attempts to acquire the company. Brent crude hovered around $90 a barrel as hopes for an advance in peace talks and reopening of the Strait of Hormuz fade.

Bitcoin hovered close to $80,000.