Stock Market: Will S&P 500 Open Up or Down Today?

U.S. stock futures are trending higher early Monday as investors digest a stark warning from President Donald Trump to Iran alongside cooling crude oil prices, while looking ahead to a week of key consumer retail earnings.

The Polymarket (CRYPTO: POL) crowd is heavily bullish for the Sept. 21 trading session. The “S&P 500 (SPX) Up or Down on September 21?” contract currently reflects an 81% chance of a higher open.

Why That Number Matters

Traders are navigating a mix of geopolitical escalations, AI sector debates, and a busy week of economic insights:

Positive Index Futures: Equity futures point to a green open across major benchmarks. Dow Jones futures rose 0.35%. S&P 500 futures advanced 0.41%. Nasdaq 100 futures gained 0.56%, and Russell 2000 futures ticked up 0.34%.

Geopolitics & Energy: President Trump warn...