So, the stock market had itself a day on Monday. The S&P 500 jumped 1.15% to close at 6,581, marking its best session since early February. The catalyst? A social media post from former President Donald Trump saying the U.S. and Iran had held "very good and productive conversations" and that there would be a five-day pause on military strikes against Iranian infrastructure.

Markets, being forward-looking creatures, liked the sound of that. Less geopolitical risk is generally good for business. But by the time Tuesday morning rolled around, the mood had shifted. Why? Because Iran said it wasn't true.

Heading into the open, the crowd on the prediction platform Polymarket (POL) is leaning bearish. Their market asking "S&P 500 Opens Up or Down on March 24?" is sitting at 73% "Down" and just 27% "Up," with over $41,000 in traded volume. That's a pretty clear sentiment check from the folks putting real money on the line.

Why The Rally Hit A Wall

Monday's optimism ran straight into a dose of reality overnight. Futures reversed course after Tehran flatly denied that any talks were taking place. Iran's parliamentary speaker called the claims "fake news" and accused someone of using them to "manipulate financial and oil markets."

That's not exactly the diplomatic progress markets were pricing in. By 2:08 AM ET, S&P 500 futures were down 0.56% at 6,597.75 points.

It creates a confusing picture. On one hand, you have a announced five-day pause on strikes, which is a tangible, time-limited de-escalation. On the other, you have one of the key parties saying the whole premise for that pause is made up. The pause itself is also conditional on the success of the very talks Iran says aren't happening. It's a bit of a head-scratcher.

This confusion was mirrored in the oil market. Crude prices tanked on Monday on the initial peace hopes—WTI settled down more than 10% at $88.13, and Brent dropped nearly 11% to $99.94. But as the story got cloudier overnight, futures bounced back. By early Tuesday, WTI futures were hovering around $91 per barrel, and Brent was at $102.92.

Adding another layer to Tuesday's open will be U.S. manufacturing PMI data due out in the morning. It's another data point that could move the needle before the bell rings.

The Case For The Bulls

It's not all doom and gloom for the optimists. For one, Trump's statement was specific and included the five-day clock, giving traders something concrete, if fragile, to hold onto. He also said Monday that both sides wish to "make a deal."

Furthermore, even after Monday's pop, the S&P 500 is still roughly 6% below its all-time high. There's room to run if the situation genuinely improves through the week.

It's also worth noting that the Polymarket crowd isn't always right, but they were spot on last time. The "S&P 500 Opens Up or Down?" market for Monday correctly resolved as "Up" after the index opened at 6,574.96, higher than Friday's close of 6,506.48. That resolution involved nearly $484,000 in traded volume.

So, will the market open up or down? You have a presidential announcement of de-escalation versus an official foreign denial. You have a time-limited ceasefire in place versus clouded diplomatic prospects. You have oil prices swinging wildly and economic data on the way. And you have a majority of prediction market traders betting on a lower open. Tuesday's opening bell should be interesting.