10-year U.S. Treasury yield rose to about 4.8% as Brent topped $92 and September rate-hike expectations firmed, weighing on U.S. equity valuations through higher discount rates and financing costs; long-duration tech stocks are most exposed. On Sept. 1 the S&P 500 opened down 0.66% and ETF SPY subsequently breached a key options-positioning area near $765. Cboe research warns that if market makers are net negative gamma, their hedging—buying into rallies and selling into declines—can mechanicall

10-year U.S. Treasury yield rose to about 4.8% as Brent topped $92 and September rate-hike expectations firmed, weighing on U.S. equity valuations through higher discount rates and financing costs; long-duration tech stocks are most exposed. On Sept. 1 the S&P 500 opened down 0.66% and ETF SPY subsequently breached a key options-positioning area near $765. Cboe research warns that if market makers are net negative gamma, their hedging—buying into rallies and selling into declines—can mechanically amplify existing moves.