“Sell in May and go away” does not beat buy-and-hold on FER: -5.7 points a year over 14 years.
Findings derived from the full panel. Each carries its number and its denominator; the computations are reproducible with artifact 0b534dd04389.
Long from the first trading day of November to the last of April; cash from May to October. Calendar rules: simulated with our seasonal engine, same costs as everything else.
The verdict compares the strategy with buying and holding FER over the same window, with round-trip costs per asset class. “Out of sample” is walk-forward: the rule is fit on one stretch and judged on the next. A result that beats in the full sample but not out of it is overfit. Full methodology in the protocol. How we test.
Open this backtest with its trades Trades (CSV)
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Finaxion Research (2026). Does “Sell in May and go away” work on FER?. Daily backtest 1962-01-01–2026-08-31, artifact 0b534dd04389. https://finaxion.app/en/research/sell-in-may/fer
Not a recommendation. Past performance does not guarantee future results.