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 hikeKLA Corp posts Q4 beat but shares tumble on limited near-term upside, soft guideFord stock jumps 4% as Q2 beats expectations and sparks guidance upgrade