S&P 500 futures saw a day of heavy selling pressure, dropping over 2.5% and moving towards the session lows. The sell-off was driven by a re-escalation of trade tensions between the U.S. and China, which led to a breakdown in negotiations. The tech sector was hit particularly hard, with Nasdaq-100 futures falling over 3.5%. The market-wide downturn was the largest single-day decline since August 1st.