At the close, the Dow Jones Industrial Average had risen 0.7 percent, the broad S&P 500 index 1.1 percent and the technology-heavy Nasdaq Composite Index 1.6 percent, reaching a new record high.
A day earlier, Trump announced that the ceasefire with Iran would be extended, but that the blockade of Iranian ports would continue.
Oil and stock prices tend to move in opposite directions: one falls when the other rises.
But on Wednesday, North Sea oil also rose 3 percent and now costs $101.40 per barrel.
A possible explanation for the stock market's ability to look beyond oil is that the start of the quarterly earnings season has shown strong profits, including from aircraft manufacturer Boeing.
