Investor optimism over an Iran peace deal waned on Thursday, with oil spiking and stocks tumbling a day after markets cheered a potential peace plan.

Hopes for a possible end to the war with Iran are pushing stocks higher again on Wall Street Wednesday, while oil prices ease. The S&P 500 rose 0.6% in its latest flip - flop after the United States delivered a plan to pause the war to Iran.

U.S. stocks rose Wednesday and global oil prices fell, as traders and investors were buffeted by constant headlines about the war in Iran.

Global equity markets rose while oil prices ​fell on Wednesday, as markets welcomed news of discussions to de-escalate the ongoing conflict in the Middle East.

Stocks fell sharply Thursday, and oil prices rose as doubt took over again from hope on Wall Street about a possible end to the war with Iran. The S&P 500 slumped 1.7% for its worst day since January and is back on track for a fifth straight losing week.

Brent crude and WTI prices were rising Thursday, while the Trump administration looks to ease fuel-cost concerns.

With airstrikes still battering Iran and missiles still targeting sites across the Middle East, some of the optimism that sent stocks rallying the day before drained out of Wall Street on Tuesday. Oil prices got back to rising,

The Investment Committee debate how to trade stocks as hopes for a resolution in Iran pushes oil lower and stocks higher.