FINAXIONResearch
Finaxion Research · “Sell in May and go away” · single stocks · Recomputed 2026-09-10

Does “Sell in May and go away” work on BLK?

“Sell in May and go away” does not beat buy-and-hold on BLK: -9.6 points a year over 27 years.

Total return
×15
Buy and hold
×138
CAGR
10.5%
Sharpe
0.53
Max drawdown
-42.4%
Trades
54
Out of sample
overfit
Years
27
1×10×100×138×20002002200420062008201020122014201620182020202220242026
StrategyBLK

Findings

  1. “Sell in May and go away” does not beat buy-and-hold on BLK: -9.6 points a year over 27 years.
  2. Against the S&P 500 over the same window: +1.7 points a year.
  3. Total return ×15 versus ×138 for buy-and-hold, with 54 trades.
  4. The result does not hold out of sample: it is overfit.
  5. Maximum drawdown -42.4%.
  6. It beats in neither half of the history (split at 2013).
  7. It ranks #52 of 232 markets for this strategy by annual excess over the S&P 500.

Findings derived from the full panel. Each carries its number and its denominator; the computations are reproducible with artifact 0b534dd04389.

Exactly what was tested

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.

How to read it

The verdict compares the strategy with buying and holding BLK 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)

Every strategy on BLK → · Full page for “Sell in May and go away” →

How to cite

Finaxion Research (2026). Does “Sell in May and go away” work on BLK?. Daily backtest 1962-01-01–2026-08-31, artifact 0b534dd04389. https://finaxion.app/en/research/sell-in-may/blk

Not a recommendation. Past performance does not guarantee future results.