Stock market today: Dow, S&P 500, Nasdaq futures slip as oil prices hit $100

US stock futures were little changed in premarket trading on Wednesday as oil prices continued their journey upward and traders shifted their expectations of a Fed rate hike in September.Futures on the Dow Jones Industrial Average (YM=F) slipped 0.6% after a downbeat session on Tuesday that saw the Dow lose over 600 points. Those on the S&P 500 (ES=F) fell 0.3%, while contracts for the Nasdaq-100 (NQ=F) edged lower by 0.4%.Oil prices reached triple digits for the first time in over a month after fighting between the US and Iran escalated and the US struck five Iranian oil tankers. Brent crude oil futures (BZ=F), the global benchmark, traded at $100 per barrel, while US benchmark WTI crude (CL=F) stood at $95 per barrel.Concerns that energy supply disruptions stemming from the war in the Strait of Hormuz will persist fed into bets that the Federal Reserve will raise interest rates next week. Traders now see a 60% chance of a 25 basis point hike this month, according to CME Group, up slightly from the odds a day ago.Inflation concerns took priority with fewer earnings reports to digest. On Wednesday, however, Chewy (CHWY) posted in-line quarterly results, while American Eagle Outfitters (AEO) will provide quarterly updates and insights into consumer spending when it reports after the bell.Apple (AAPL) will also kick off a new era today when CEO John Ternus takes the stage for the first time for the company's annual iPhone launch event.