US stocks: Dow hits record high as oil slides; SpaceX shares soar

The Dow Jones Industrial Average reached a new record high on Tuesday, driven by falling oil prices amid optimism for a U.S.-Iran peace deal. Meanwhile, SpaceX's market value surged past Amazon's, positioning it as the fifth most valuable U.S. company. The S&P 500 saw a slight gain, while the Nasdaq Composite experienced a minor loss.