S&P 500 Momentum Continued Its Dominant Run in May

Physics tells us that something in motion stays in motion. With a month-to-date gain of 7.4% for momentum, according to data from S&P Global, other style-box factors essentially got out of momentum's way.

Momentum's strength comes on the heels of broader equities resilience as evidenced by a 5.3% rise in May. This marked an eight-week winning streak, the longest positive run since 2023. From a macro level, optimism surrounding a U.S.-Iran resolution, cooling oil prices, and stronger-than-anticipated corporate earnings have been prime performance catalysts.

MTD Momentum Factor Dominance in May

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A Momentous May

The S&P 500 Momentum's 7.4% gain in May marks its second-best relative month and its third-best absolute monthly performance since the index's inception almost 12 years ago. Rolling three-month (from March to May) data from S&P further revealed that the momentum index exceeded the broader benchmark by 16.0%. For perspective, this represents the single greatest three-month run in its nearly 12-year history.

With such a strong performance run, it's natural to think that a pullback is inevitable. S&P data, however, shows signs of historical resilience. When evaluating the top 10 three-month excess performance periods since 2014, the results of subsequent three-month periods are practically a 50-50 coin toss. Momentum continued to beat the benchmark in half of the instances, while trailing in the other half. When pullbacks did occur, none were severe enough to nullify the previous gains achieved during the initial run.