ETH-BTC Ratio Z-Score Mean Reversion Pairs Long-Short on 4H

A dollar-neutral pairs trading strategy on the ETH/BTC ratio using 4-hour bars on Binance USD-M perpetuals. ETHUSDT.BINANCE is the primary instrument; BTCUSDT.BINANCE is the secondary (hedge) leg. Every 4H bar close, the strategy computes the log-price ratio R = log(ETH_close / BTC_close), then a 30-bar rolling mean (mu) and standard deviation (sigma) of R, yielding a z-score Z = (R - mu) / sigma. When Z falls below -2.0 the ratio is depressed relative to its recent equilibrium and is statistically likely to mean-revert upward, so the strategy goes LONG ETH + SHORT BTC (in equal USD notional, ~25% of equity each leg, dollar-neutral pair). When Z rises above +2.0 the ratio is elevated and likely to revert downward, so the strategy goes SHORT ETH + LONG BTC. Exits occur when Z crosses back through 0 (full mean reversion), or after a 20-bar time stop, or on a -8% per-leg drawdown emergency stop. This hypothesis is structurally orthogonal to every strategy in the pipeline (none are pairs trades, none use a relative-value ratio as the signal) and orthogonal to every failure pattern in the log: it is NOT single-instrument (so it cannot suffer the rare-event regime concentration that killed XRP/ADA/DOGE/LINK/ETH-trend), it is NOT a single-bar pattern (the z-score aggregates 30 bars of co-movement), it is NOT a directional breakout (it is dollar-neutral relative-value), it is NOT mean-reversion-with-technical-gates (no Bollinger or RSI overlay; pure z-score), and it does NOT depend on supplementary data (avoiding the verification framework's no-trades failure on OI/L-S-ratio strategies). Two free parameters total: lookback (30) and z-threshold (2.0) — the lowest parameter count of any hypothesis this session, minimizing overfitting surface. Expected trade frequency: |z| > 2.0 events at 4H frequency occur ~80-150 times per year on the ETH/BTC ratio based on historical co-movement statistics, well above the walk-forward viability floor and the explicit 25-trade/year minimum cited in multiple abandonment notes. The dollar-neutral pair structure also means the strategy is market-direction-agnostic — it earns from co-movement disequilibrium rather than from beta exposure to crypto, which means 2022 bear-market PnL is structurally as productive as 2021/2024 bull-market PnL, breaking the regime-concentration curse that killed every single-alt strategy in the failure log.