OKX Idiosyncratic Capitulation Absorption, BTC-Beta-Hedged: long an OKX alt swap + short beta-weighted BTCUSDT.OKX after a <=-2.5-sigma 24h BTC-residual selloff on >=1.5x normal dollar volume, fixed 24h clock (14 pre-2021 OKX USDT swaps, 4H, pure OHLCV, market-neutral, flat ~95% of the time)

Cross-sectional, event-driven, market-neutral (long alt / short BTC) strategy on OKX USDT perpetual swaps, 4-HOUR bars, OHLCV only, no supplementary feed. Universe (fixed before any return was examined): the 14 OKX swaps with continuous 4H history starting before 2021-01-01: ETC, BCH, DOT, LINK, ATOM, AAVE, UNI, XLM, ALGO, FIL, LTC, SUSHI, CRV, COMP (all <BASE>USDT.OKX), plus BTCUSDT.OKX as the hedge leg. Point-in-time rule: a name can trigger only after it has 180 completed 4H bars (30 days) of its own history at that bar. Use is_listed()/universe_at() so a leg that stops trading is never entered (OKX keeps no delisted swaps, a known residual survivorship limit: say so in the report). Mechanism, with instrument removed: when one coin sells off hard relative to what BTC explains, and does so on a burst of traded value, the selling is a coin-specific forced/impatient flow (single-name liquidation chains, unlock or treasury dumps, a large holder exiting). Liquidity providers who absorb it demand a premium, so the coin's BTC-residual price partly reverts over the next ~half day to a day (the immediacy premium of Grossman-Miller 1988 / Nagel 2012, measured on the idiosyncratic component). Hedging with BTC strips out the market-wide crash/rebound component, so the trade is a bet on the residual only and is long-short. Why this test is distinct from what the factory already holds: the promoted 'Spot-Led Idiosyncratic Alt Selloff Rebound' (Binance USD-M) requires a spot-led confirmation and the Bybit volume-share version requires a Bybit venue-share spike plus cross-venue Binance bars. This one asks whether the plain residual-shock + volume-climax absorption exists on a third venue with one venue's data alone, which is also the no-confirmation baseline lesson L214 asks for. Venue OKX is 3.5% of the corpus (target >=5%) and long-short is 24% (target >=45%). The factory's OKX 4H aggressor-burst CONTINUATION panel on 12 of these same names lost -0.71% per trade over a 24h hold (464 trades), which is consistent with reversal rather than continuation after one-sided bursts on these swaps; only the long (fade-the-down-shock) arm is traded here because lesson L230 says the short arm of absorption must be measured separately and the long arm is the one with survivors. Pre-registered fixed-rule measurement (Research Lead pre-study, OKX 4H catalog 2020-2026, rules exactly as below, gross of costs, hedged forward log return of alt minus beta x BTC, one event per name per hold window): z<=-2.5 and volume ratio>=1.5 gave 625 events, mean +0.47%, median +0.31%, hit rate 53.8% at a 24h hold; 867 events, mean +0.50% at 12h; mean turns negative by 48-72h (idiosyncratic losers keep losing at longer horizons, so the clock must stay short). Per-year means at 24h: 2020 +1.39%, 2021 +1.87%, 2022 +0.36%, 2023 -0.59%, 2024 +0.26%, 2025 +1.48%, 2026 YTD +0.11%: positive in 6 of 7 years but uneven, 2023 is negative. This sets the arithmetic, not acceptance. Cost arithmetic: alt leg round trip 0.10% (OKX taker 0.05% x 2), BTC hedge leg beta (median ~1.0) x 0.10%, so about 0.20% of alt notional per event, plus funding over 24h (small, sign varies). Gross capture ~0.47% -> net ~0.27% per event on alt notional, about 2.3x the cost. Because the platform measures avg_trade_return_pct per closed position, and the hedge leg is its own position with near-zero expected return, the measured per-position average will be roughly half the per-event net (~0.13-0.18%); the analyst should read the per-event (paired) figure as the economic test. Execution: decisions on the 4H bar close; orders are market orders at that close, which on a 24/7 venue is the faithful equivalent of the next-bar-open fill (substitution stated). The protective stop on the alt leg is an intrabar protective stop (reduce-only stop-market matched by the platform inside the bar in backtest and paper; live mirrors the fills), not an exchange-resting order; when the alt stop fires, the hedge leg is closed at the same bar's close. Hedge positions on BTCUSDT.OKX are NETTED across concurrent events (one net short BTC position = sum of each open event's beta x alt notional), adjusted on each entry/exit; this is the net-exposure equivalent of per-event hedges (hedge_mode is unsupported, and only net exposure is needed). Check legs_balanced() after each adjustment.