Turn of Month
Long in the first/last configured weekday-count windows of each calendar month. The Monday-Friday calendar is known without future price rows; it is an approximation, not an exchange holiday calendar.
At a glance
What the backtest shows
- Beat buy-and-hold on 2 of 10 markets by annual return over 5 years.
- Had a smaller maximum drawdown than buy-and-hold on 8 of 10 markets.
- Best market by Sharpe ratio: SPY (Sharpe 0.47, CAGR 4.0%).
- Weakest market: EURUSD=X (Sharpe -0.51, CAGR -2.2%).
Equity curve
Score and risk profile
Each bar is a percentile against every strategy on the same market and window (100 = best).
How it held up in sell-offs (SPY)
| Period | Strategy | Buy & hold |
|---|---|---|
| Q4 2018 sell-off | +2.6% | -19.2% |
| COVID crash (Feb–Mar 2020) | -3.3% | -33.7% |
| 2022 bear market | -2.7% | -24.5% |
| Market above its 200-day average (annualized) · 81% | +3.9% | +12.5% |
| Market below its 200-day average (annualized) · 19% | +7.5% | +19.8% |
Sell-off dates follow the US stock market. Above/below the 200-day average uses the previous day's position, so there is no look-ahead.
Out-of-sample check (SPY)
| Check | Value |
|---|---|
| Chosen parameters on their 3-year training windows (average Sharpe) | 0.84 |
| Same parameters in the following 6 months, when traded (Sharpe) | 0.62 |
| Default parameters over the same months (Sharpe) | 0.55 |
| Parameter re-selections / changes | 28 / 14 |
| Parameter settings with a positive Sharpe (full history) | 9 of 9 |
| Sharpe across settings: worst / median / best | 0.36 / 0.53 / 0.68 |
Out-of-sample periods start on 2013-01-04. Training-window figures are flattered by picking the best of 9 settings; the out-of-sample figure is what the strategy actually earned. A large drop, or a result that depends on one setting, points to overfitting. How walk-forward testing works.
Results by market (5 years)
| Market | CAGR | Buy & hold CAGR | Sharpe | Max drawdown | Buy & hold max DD | Volatility | Arena Score |
|---|---|---|---|---|---|---|---|
| SPYSPDR S&P 500 | 4.0% | 11.6% | 0.47 | -15.1% | -24.5% | 9.3% | 52 |
| GLDSPDR Gold Shares | 4.4% | 16.4% | 0.43 | -13.9% | -28.3% | 11.6% | 50 |
| DBAInvesco DB Agriculture | 0.3% | 8.8% | 0.08 | -12.6% | -15.9% | 7.0% | 34 |
| DBCInvesco DB Commodity Index | -1.6% | 10.8% | -0.10 | -31.2% | -27.3% | 10.7% | 29 |
| UNGUnited States Natural Gas | -8.2% | -30.7% | -0.14 | -62.2% | -93.3% | 29.3% | 63 |
| BTC-USDBitcoin | -8.2% | 2.6% | -0.20 | -50.4% | -75.9% | 19.5% | 26 |
| USOUnited States Oil Fund | -6.4% | 20.2% | -0.24 | -46.6% | -36.2% | 19.7% | 27 |
| ETH-USDEthereum | -12.4% | -15.1% | -0.29 | -64.0% | -79.0% | 22.7% | 36 |
| SLViShares Silver Trust | -8.8% | 15.2% | -0.29 | -52.6% | -57.8% | 22.5% | 15 |
| EURUSD=XEUR/USD | -2.2% | -0.7% | -0.51 | -14.4% | -17.2% | 4.2% | 24 |
Strategy metrics use daily returns without trading costs. Buy-and-hold figures are for the same market and window. Rows are sorted by Sharpe ratio.
SPY across time windows
Rules
Entry
Hold when at most Start_Days calendar weekdays have elapsed Hold when fewer than End_Days calendar weekdays remain
Exit
Exit outside turn-of-month window
Indicators
Elapsed/remaining Monday-Friday calendar weekdays
Inputs
End_Days = 3 Start_Days = 3
Position sizing
Fixed 100% allocation
Risk controls
Simple calendar-based rule
Strategy evidence
- BTC-USD · Inspect evidence 2026-11-10
- DBA · Inspect evidence 2026-11-10
- DBC · Inspect evidence 2026-11-10
- ETH-USD · Inspect evidence 2026-11-10
- EURUSD=X · Inspect evidence 2026-11-10
- GLD · Inspect evidence 2026-11-10
- SLV · Inspect evidence 2026-11-10
- SPY · Inspect evidence 2026-11-10
- UNG · Inspect evidence 2026-11-10
- USO · Inspect evidence 2026-11-10
Only available, validated bundles appear below. Missing evidence is not a passing validation result.
Evidence coverage
10 / 10 declared strategy–market pairs validated
Notes
- Version 2 uses a fixed Monday-Friday calendar and ignores exchange holidays; weekend observations can stay inside a contiguous month-turn window.
- The earlier version counted future rows in the downloaded month and could revise earlier targets as new observations arrived.
- Institutional rebalancing at month-end
- Payroll and pension fund flows
- Well-documented calendar anomaly
Related strategies
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Backtests are historical simulations on daily data and do not include commissions or slippage. They do not guarantee future results and are not investment advice. See the methodology for how every strategy is tested.