Under “Total Gridlock” – a split Congress – the results weren’t encouraging. Since 1900, the 500 rose only 2% per year, performing better under Republicans than under Democrats. Since 1945, the market gained only 3.5% per year.
The rationale behind this sub-par performance could be that gridlock generates uncertainty, says Stovall, and Wall Street hates uncertainty. He emphasizes though that there have been limited examples from which to draw conclusions – only 12 since 1900 and eight since 1945.