The S&P 500 index and the tech-heavy Nasdaq Composite Index both lost 0.3 percent, while the Dow Jones Industrial Average fell 0.4 percent.
These were more subdued declines than those on stock exchanges in, for example, Stockholm, London, Paris and Frankfurt, which all closed in decidedly deeper red.
Following attacks on energy infrastructure in the US and Israel's war on Iran, Brent crude surged to around $118 a barrel. During the day, the price fell back and by 9 p.m. it was just over $107.
Japan, along with several European countries, announced earlier on Thursday that they will help open the Strait of Hormuz, but exactly how this will happen remains unclear.
