US equity-index futures surged early Thursday as Washington and Tehran announced a interim agreement to reopen the Strait of Hormuz. The move erased much of the risk premium that had built up after weeks of tension over the strategic waterway, which carries a sizable share of global oil shipments. Traders today greeted the news with optimism across major indices.

The immediate market reaction was a 1.3% rise in S&P 500 index futures by 7:45 a.m. New York time, signaling a swift shift in sentiment. Energy stocks, long pressured by supply‑risk concerns, rallied alongside broader indexes, while currency markets saw the dollar ease against peers. The price lift reflects investors’ calculation that a reopened Hormuz will dampen any near‑term oil price spikes.

While the interim accord eases immediate geopolitical risk, it does not resolve underlying disputes that could resurface. Nonetheless, the rally underscores how quickly markets price diplomatic breakthroughs. Analysts will watch for concrete timelines on vessel traffic and any supplementary sanctions relief, factors that could sustain the current upside or trigger another correction in the weeks ahead for equity investors overall.