Stocks experienced a decline, bond yields rose, and oil prices surged after President Donald Trump announced that the ceasefire between the US and Iran was over. S&P 500 futures initially slid by as much as 1.1% before recovering some losses, while Brent crude oil advanced 4.5% to around $77.50 a barrel. This geopolitical upheaval follows US strikes against Iran in response to attacks on ships in the Strait of Hormuz, with Trump labeling the ceasefire "a waste of time." Violeta Todorova, a senior research analyst at Leverage Shares, noted that this marks the most serious rupture in an agreement that had been unraveling for weeks, unsettling market complacency that had viewed the June memorandum of understanding as a durable de-escalation.

The escalation is inducing a flight from risk, despite earlier investor confidence stemming from an April ceasefire and a subsequent US-Iran memorandum of understanding aimed at avoiding a prolonged conflict. Markets had seen a rally since late March, bolstered by a strong earnings season driven by the potential of artificial intelligence. However, Michael Field, chief equity strategist at Morningstar, stated that "overlapping negative news flow is pushing markets down now, and with no major earnings coming out in the next few days to change that trend, it seems there will be little respite for markets."

Bond markets also reacted significantly; European bonds tumbled as traders increased bets on central bank interest rate hikes this year. The yield on 10-year gilts jumped eight basis points to 4.93%, and Treasuries extended Tuesday's selloff, with the 10-year Treasury yield advancing one basis point to 4.57%. Oil and gas stocks performed well in US premarket trading, while chipmakers, including Micron Technology Inc. and SanDisk Corp., saw declines of over 3%. All members of the Magnificent Seven were trading lower, with Microsoft Corp. leading the losses. West Texas Intermediate crude rose 4.5% to $73.62 a barrel, and spot gold fell 0.9% to $4,068.80 an ounce.