Cohen-Malloy-Pomorski: open-market buys by officers/directors whose trading is NOT a yearly routine (traded each of the past 3 years, never in the same month). Biggest 10 by value, held 30 days.
Jan 3, 2017 to Oct 27, 2026, after trading costs. After a 28% tax on gains: +6.0%/yr vs +12.1%/yr for the S&P 500 (-6.1% a year). Worst drop -52%.
Verdict: Not proven
| Year | Strategy | S&P 500 |
|---|---|---|
| 2017 | +15.1% | +21.4% |
| 2018 | -7.6% | -4.9% |
| 2019 | +21.0% | +30.6% |
| 2020 | +6.0% | +18.2% |
| 2021 | +18.1% | +28.3% |
| 2022 | +15.6% | -18.0% |
| 2023 | +9.4% | +25.9% |
| 2024 | +1.5% | +24.7% |
| 2025 | +6.1% | +17.6% |
| 2026 | +4.7% | +13.7% |
Trades happen the trading day after the information became public, so there's no hindsight. We charge 5 basis points per trade, cap any stock at 25%%, keep 2%% in cash, and keep companies that were later delisted or acquired. Returns include dividends. The strategy's rules were frozen before the results were known, and we report "not proven" when the edge could be luck (t-statistic below 2).
Free to view the live paper portfolio.