With derivative markets pricing in a staggering 36 percent chance of a surprise rate increase, traders are bracing for a high-wire event that threatens to shatter the fragile summer market calm. To prepare clients for the impending fallout, JPMorgan's U.S. Market Intelligence desk mapped out five stark scenarios detailing how the stock market could react once the decision hits the tape. An extreme half-point rate hike—given a slim 1 percent chance—could spark outright panic, triggering a 2 percent to 4 percent plunge in the S&P 500. Despite the heightened anxiety on trading floors, JPMorgan's market intelligence team believes investors may be overestimating the risk of a rate hike. Related articlesJPMorgan maps Fed decision scenarios as Wall Street braces for surprise rate hikeAs Claude disrupts stock market, Anthropic researcher warns 'world is in peril'Wolfe Research outlines eight risks that could spark stock declines in 2026