The S&P 500 ended its more than 5.5% four-day rally on Wednesday, but the broad index's surge to new records is recalibrating prediction market traders' outlook for how high it can go.

Speculators on prediction market platform Kalshi now give a 2-in-3 chance that the index will cross 8,000 in 2026. As of Wednesday's close, the index is just about 3.6% away from that level.

The contracts on Kalshi ask speculators if the S&P in 2026 will trade above various levels. The platform uses Google Finance to resolve the contracts.

While the S&P 500 surged in April and May from its lows during the U.S.-Iran war, the index didn't do much in late June and July as investors moved out of key momentum names involved in the artificial intelligence trade that had experienced enormous rallies. However, a rotation into other stocks masked the turmoil.

The S&P's four-day rally was driven by a slew of catalysts: Easing tensions between the U.S. and Iran in the Middle East, a strong earnings season and the near-collapse of Leopold Aschenbrenner's Situational Awareness fund.

Rather than June and July marking the end to the AI rally, analysts broadly view it as a healthy reset and expect that the bull market can now build momentum again.

"Our investment thesis remains intact," Truist Wealth's chief market strategist Keith Lerner wrote in a Tuesday note. "Earnings remain our north star. Estimates continue to trend higher, economic growth remains resilient, and market participation has improved. Those are not conditions typically associated with the end of a bull market."

Odds that the S&P 500 marches even higher are rising, too. Kalshi traders now place a one-in-three chance to cross 8,200 this year.

Disclosure: CNBC and Kalshi have a commercial relationship that includes customer acquisition and a minority investment.