The S&P 500 closed above the 7,600 level for the first time on Tuesday, extending its record-setting rally, but Polymarket traders are leaning toward a weaker start for the benchmark index on Wednesday.

The S&P 500 gained 0.13% to finish at a record 7,609.78 on Tuesday. The June 3 Polymarket contract implied a 47% probability that the index will open higher, giving a slight edge to a lower open.

Why That Number Matters

Tuesday’s close underscored the strength of the market’s AI-driven rally.

However, investors continue to monitor developments in the Middle East after U.S. Central Command said American forces intercepted Iranian ballistic missiles and drones and carried out “self-defense strikes” on Iran’s Qeshm Island following attempted attacks across the region.

Market participants are also weighing whether the benchmark’s rally can ...