Retail-Capitulation-Confirmed Down-Shock Absorption on Hyperliquid: buy a Hyperliquid alt perp at the close of a <=-2-sigma UTC day ONLY when the same coin's Binance USD-M GLOBAL long/short ACCOUNT ratio fell >=5% (log) that day (retail longs gave up), fixed 3-day clock (27 HL perps, Binance perps as signal-only legs, 1-DAY, long-only event panel, max 6 concurrent at 10%, flat most of the time)

Original Research Lead hypothesis. It is a cross-venue test of a NEW conditioning variable for the one design family that keeps surviving here (flat-most-of-the-time down-shock absorption with a fixed clock, lessons L224/L230), answering the analyst's 2026-10-18 OKX post-mortem request for 'positioning/liquidation data that marks forced selling directly, rather than BTC return z-scores'. The promoted Binance-spot panel used the OPEN-INTEREST drop (leverage being closed). This hypothesis uses a different and complementary positioning feed: the Binance USD-M perp GLOBAL long/short ACCOUNT ratio (`long_short_ratio` in the Binance metrics mirror, 5-minute, since 2021-12), which counts ACCOUNTS, i.e. the retail crowd, not notional. A large down day on which the share of accounts that are long FALLS means the crowd capitulated: retail longs sold or were stopped out, price-insensitive selling that liquidity providers are paid to absorb (Grossman-Miller 1988; Nagel 2012). A down day on which the account ratio RISES means retail is buying the dip into informed or directional selling; the crowd still has to unwind, so it should not revert (the classic contrarian reading of retail positioning). The trade is placed on HYPERLIQUID perps (13.3% of the corpus vs the >=20% target; cross-venue 10% vs >=15%), with each coin's Binance USD-M perp carried as a SIGNAL-ONLY extra instrument that is never traded: its `global_account_ratio_by_instrument` / metrics feed supplies the account ratio. Hyperliquid 1-DAY candles in our catalog reach back to 2020, so the binding history is the Binance metrics feed (2021-12-02 onward, about 4.9 years). Universe (point in time, fixed list, chosen by rule not by result): the 27 HL perps that also have a Binance USD-M perp with metrics history and an HL 1-DAY history from before 2023-06: LINK, ADA, DOGE, XRP, LTC, DOT, ATOM, ETC, BCH, AVAX, UNI, AAVE, SOL, NEAR, APT, ARB, OP, INJ, SUI, FIL, TRX, BNB, LDO, CRV, RUNE, SNX, STX (names whose HL or metrics series do not exist on a date are simply ineligible on that date: `is_listed()` + data present, never a price-only fallback). Eligible at a bar only if: listed, >= vol_lookback+1 daily HL bars, and an account-ratio observation (> 0) at or before the current close and at or before the previous close, each within 3 hours of that close (point-in-time `supp_as_of`). Pre-registered event count (counted on HL 1-DAY closes and Binance metrics, 2021-12-02 to 2026-10-18, z from a 60-day trailing std of log returns excluding today): z <= -2.0 AND dlog(account ratio) <= -0.05 gives 405 name-events on 97 distinct UTC dates (about 20 dates/year). Per lesson L238 the honest evidence unit is the DATE: 97 dates. Neighbours: drop <= 0 -> 556 events / 121 dates; drop <= -0.08 -> 340 / 83; z <= -2.5 with drop <= -0.05 -> 256 / 59. The L237 floor of ~30 qualifying events is cleared at every neighbour. The comparator subset (z <= -2 with the ratio RISING) has 650 events on 198 dates. Incremental-expectancy pre-registration (lessons L214/L217): the comparator is the SAME down-shock rule on the SAME HL names when the account ratio ROSE. Prediction: capitulation events (ratio drop >= 5%) earn a mean 3-day after-cost return at least 0.4 percentage points higher than ratio-rising down-shocks. If they do not, the positioning condition adds nothing and the premise is falsified even if the panel is profitable. The developer must log, for EVERY down-shock with z <= z_threshold on an eligible name, the dlog ratio, the dlog OI, whether it was traded or skipped (and why: condition, concurrency cap), so the analyst can compute both subsets, and the overlap with the already-promoted OI-flush condition, from one run. Execution: decisions on the close of each HL 1-DAY bar (00:00 UTC). A market order at the signal bar's close is the faithful equivalent of a next-bar-open fill on this 24/7 venue (`next_bar_open_fill` is use_equivalent; substitution named here). No stops. Risk-control route (b): fixed time exit plus capped sizing: 10% of equity per leg, at most 6 concurrent legs (60% gross), leverage 1x, so no single position exceeds 100% of equity. Under the conservative risk profile: a 10% leg in an alt with ~100-130% annualized vol contributes ~10-13% annualized vol (cap 120%); the book stays far from liquidation at 0.6x gross; worst single-trade loss at 10% notional is bounded near 3-5% of equity even on a further -40% leg move (cap 15%). Intended realized vol ~15-25%/yr. Fee arithmetic: HL round trip ~0.09% taker plus ~3 days of hourly funding (after a crash funding is usually near zero or negative, i.e. longs are paid; budget 0.05%) plus modeled slippage: ~0.15-0.20% all-in. A <=-2-sigma day on these alts is typically -6% to -12%. The promoted absorption panels captured 0.9-1.9% per trade over 2-3 days; I expect a gross 3-day capture of about 0.9% on capitulation events, so ~0.7% net, more than 4x the round trip and above the 0.15% HL floor. Buy-and-hold comparison (lesson L224): an equal-weight buy-and-hold of these alts drew down roughly 80-90% in 2022. The panel is flat on roughly 85-90% of name-days with at most 60% gross, so I pre-register a 25% max drawdown (futures default 20% would be flattering for a long-only alt panel that buys crash days in clusters). What distinguishes this from abandoned neighbours: the HL capitulation-close next-day transfer (underpowered) conditioned on range/close-location only and held 1 day; the HL idiosyncratic down-shock rebound and HL volume-confirmed daily panel (promoted) condition on price/volume; the OKX stress-day/beta-overshoot runs (underpowered) condition on BTC z-scores. None conditions on retail account positioning, and none uses a second venue's positioning feed to time an HL trade.