Stock market today: Dow, S&P 500, Nasdaq futures mixed as US-Iran war escalates, inflation jitters return

US stock futures were mixed in premarket trading on Wednesday as rising oil prices and bond yields sent ripple effects across markets.Futures on the Dow Jones Industrial Average (YM=F) rose 0.2%, and S&P 500 (ES=F) edged higher, while contracts for the Nasdaq-100 (NQ=F) slipped 0.1%, extending losses after a losing day on Wall Street.Stocks got off to an unsteady start in September as the war in Iran escalated, causing Brent (BZ=F) crude oil prices to jump above $95 per barrel. On Tuesday, President Trump threatened to hit Iran "much harder" if the nation retaliates against a barrage of airstrikes launched on Tuesday.The latest flare-up in hostilities has amplified fears of rising inflation, driving up bond yields in the process. On Tuesday, the 10-year Treasury yield (^TNX) rose to 4.79%, while the 30-year (^TYX) climbed to 5.27%, affecting a range of assets.A trade standoff with Canada also remained in focus, with Canadian Prime Minister Mark Carney saying the US and Canada could resume trade discussions when Americans "stop throwing shade" and "start being serious" about negotiations. However, Treasury Secretary Scott Bessent downplayed the idea that the US was in a trade war with Canada.On Wednesday, ADP's private-sector hiring data will offer clues about the health of the labor market after job openings appeared frozen, providing insights into what Friday's monthly jobs report may show.Earnings from Broadcom (AVGO) and Snowflake (SNOW) are also on the docket on Wednesday.