A MARKET-NEUTRAL statistical-arbitrage pairs trade on the two most cointegrated crypto majors: ETHUSDT.BINANCE and BTCUSDT.BINANCE (USD-M perps, 4h bars). Signal = the z-score of the log(ETH/BTC) price ratio versus its own rolling mean over a lookback window (default ~180 bars ≈ 30 days). When the ratio stretches ≥ entry_z (default 2.0) ABOVE its rolling mean (ETH richly outperforming BTC), SHORT ETH perp + LONG equal-notional BTC perp, betting on convergence; symmetric when it stretches ≥2σ BELOW (long ETH / short BTC). The position is delta-neutral in dollar terms (equal-notional legs) so it carries no crypto-beta — its P&L is the RELATIVE move of ETH vs BTC, not the market direction. Exit on convergence to |z| ≤ exit_z (default 0.5). This is a deliberately DIFFERENT family from the funding-carry basket that just collided (twice abandoned fee_edge): its edge is not a sub-basis-point funding cash flow that alt legs can't clear, but a multi-percent ratio reversion — ETH/BTC 2σ deviations are typically 2–4%, an order of magnitude above the ~0.20% two-leg USD-M round-trip (4 fills × ~0.05%), so it is structurally fee-viable where the N-leg carry baskets and cross-sectional reversal baskets (L12) are not. A ROLLING (adaptive) mean absorbs slow structural re-ratings of the ratio, and a hard divergence stop at |z| ≥ 3.5 exits when cointegration appears to be breaking rather than reverting, capping the classic stat-arb tail. Returns are earned in every regime the ratio oscillates (ranging and trend-then-reconverge), so there is no single-regime/2021 bull-spike concentration — the killer of every trend sibling this session — and no options trade-count wall.