JPMorgan Chase expects the S&P 500 index to fall by about 0.5% on Wednesday if the Democratic Party wins both chambers of Congress in the US midterm elections, CNBC reported. The bank's traders also anticipate the index could rise by up to 1% on Wednesday if the Republican Party retains the Senate. Citi strategists believe a scenario where Republicans lose the House but keep the Senate could provide a boost for the stock market through year-end. Jonathan Krinsky, Chief Market Technician at BTIG, cautioned that the S&P 500 has already seen significant gains this year ahead of the elections, so the usual post-election rally may not materialize. The above are conditional assessments by institutions and do not represent election outcomes or definite market movements.