U.S. stock futures were mixed Wednesday after Tuesday's uneven session, with the S&P 500 and Dow Jones higher while Nasdaq 100 and Russell 2000 futures declined. During an address to the UN General Assembly, President Donald Trump warned that he could "annihilate" Iran if negotiations fail. The day's earnings calendar includes Cintas, Paychex, General Mills and Cracker Barrel. Treasury yields stood at 4.96% for the 10-year note and 4.77% for the two-year note, while CME Group's FedWatch tool showed a 57.6% probability of a Federal Reserve rate hike after its October meeting. Analysts led by Professor Jeremy Siegel said equities could continue rising if the 10-year yield remains below 5%, but a sustained move above that level would make further gains more difficult. September flash U.S. manufacturing and services PMI data are due at 9:45 a.m. ET. Bitcoin rose 0.90% to $86,148.31, while oil fell and gold declined.