The Dow Jones industrial average rose 0.4 percent, the broad-based S&P 500 index closed unchanged and the tech-heavy Nasdaq composite index rose 0.1 percent.
Thus, the Dow closed at a new record high.
After positive talk about a possible peace deal with Iran, US President Donald Trump said he was "not happy" with the negotiations - dampening hopes.
The situation surrounding Iran is still highly fluid, says Adam Turnquist, strategist at financial advisory firm LPL Financial.
Oil prices still fell 4.4 percent during the day. A barrel of North Sea oil now costs $95.20.
Semiconductor company Micron continued to rise, up 3.6 percent, the day after a 20 percent rise when stock analysts highlighted the stock.
Industry peers Qualcomm and Intel had a heavier Wednesday, falling 6.2 percent and 1.4 percent, respectively.
