Deleveraging-Confirmed Capitulation, Cross-Venue Transfer to Hyperliquid Perps: buy a Hyperliquid alt perp at the close of a <=-2-sigma UTC day ONLY when the same coin's Binance USD-M perp open interest (coin units) fell >=8% that day, fixed 3-day clock (19 HL perps, Binance OI as forced-selling marker, 1-DAY, long-only event panel, max 6 legs at 10%, flat most of the time)

Original Research Lead hypothesis. It is a fresh-venue test (lesson L228) of the forced-selling marker that the OKX stress-day post-mortem asked for and that was then promoted on Binance SPOT ('Deleveraging-Confirmed Spot Capitulation': 212 trades, avg trade 1.86%, Sharpe 0.50, max DD 20.5%). Here the trade is placed on HYPERLIQUID perps (13.3% of the corpus against a >=20% target, and the venue live trading is moving to), and the signal is read on a DIFFERENT venue: the one-day change in the coin's Binance USD-M perpetual open interest in CONTRACT (coin) units. Binance USD-M carries most of the leveraged alt open interest, so a large Binance OI drop on a large down day marks liquidations and margin-call selling across the market; Hyperliquid perps are arbitraged to the same price by cross-venue traders, so the price-insensitive selling and its rebound show up on HL. A down day with RISING OI is a different event (new shorts opening, i.e. directional selling) and is not traded. Why a cross-venue signal: Hyperliquid's own OI history in our store starts 2026-09, which is too short. The platform's per-leg OI loader (`open_interest_by_instrument`) only maps BINANCE / BINANCE_SPOT / BINANCE_CM legs. So every HL trading leg is paired with its Binance USD-M perp as a SIGNAL-ONLY extra instrument (never traded). Its daily bars are subscribed only so the OI series is attached under that leg's id. The strategy reads OI point in time with the OI observation at or before the decision bar's close (latest within 2 hours). If either OI reading is missing it skips the name; it never falls back to a price-only rule. Universe (fixed list, every coin has HL daily bars and Binance USD-M metrics OI from 2021-12): LINK, ADA, XRP, LTC, DOT, ATOM, ETC, BCH, TRX, XLM, FIL, AVAX, UNI, AAVE, SOL, NEAR, ALGO, SAND, DOGE. Each leg is gated by `is_listed()` and needs at least 61 daily bars. The effective window is 2021-12-03 to 2026-10 (OI starts 2021-12). Pre-registered event count (lessons L237/L238/L242; counted on HL 1-DAY closes and Binance metrics OI with a fixed rule, not a strategy backtest): z = today's log return / std of the prior 60 daily log returns. z <= -2 with an OI drop of at least 8% gives 252 name-events on 84 DISTINCT UTC dates (about 17 dates a year), by year 2022: 53/21, 2023: 76/22, 2024: 72/21, 2025: 27/11, 2026: 9/7 (2021: 15/2). The honest evidence unit is the 84 dates. Raw (unsized, pre-cost) 3-day forward HL close-to-close return: mean +2.45%, median +1.17%. Neighbours: z<=-2 with OI drop >=5% gives 359 events on 107 dates, mean +2.27%; z<=-2.5 with OI drop >=8% gives 157 events on 52 dates, mean +1.96%; z<=-1.5 with OI drop >=8% gives 401 events on 150 dates, mean +1.94%. The 2022 bear year was negative (-1.13% mean on 21 dates), so a sustained bear regime is the known weak spot. Incremental-expectancy pre-registration (lessons L214/L217): the comparator is the SAME z<=-2 down-shock with Binance OI RISING that day: 347 events, mean 3-day forward +0.26%, against +2.45% for flush events. Prediction: in the backtest, flush trades beat the rising-OI subset by at least 1.0 percentage point per event. The developer logs every z<=z_threshold down-shock (name, date, OI change, traded or not, 3-day forward return) so the analyst can split the two subsets from the same run. If the flush subset does not beat the rising-OI subset, the OI conditioning adds nothing and the premise is falsified even if the panel is profitable. Execution: decisions on the close of each 1-DAY HL bar (00:00 UTC). On this 24/7 venue a market order at the signal bar's close is the platform's faithful equivalent of a next-bar-open fill (`next_bar_open_fill`: use_equivalent). HL hourly funding paid or received while long is in PnL. Risk-control route (b): a fixed time exit plus capped sizing. Each leg is 10% of equity with at most 6 concurrent legs, so gross exposure is at most 60% and unlevered (leverage 1.0). No stop-loss. Risk profile (conservative): one 10% leg of a ~100%-annual-vol alt contributes about 10-13% annualized vol, far under the 120% per-position cap. The book is flat about 85% of days, so expected realized vol is about 20-30% annualized, well inside the 60% band. At 1x there is no liquidation risk. The worst plausible single trade (-40% on one 10% leg) is a 4% equity loss, under the 15% cap. Fee arithmetic: the HL round trip is ~0.09% taker plus modeled slippage and ~3 days of funding (typically 0.01-0.03% per day on longs, about 0.05-0.10% per trade). Total friction is about 0.2% against a raw measured mean of +2.45% and median of +1.17%. I expect a net capture of about 1.0-1.5% per trade, more than 5x friction and far above the 0.15% HL floor. Buy-and-hold comparison (lesson L224): an equal-weight buy-and-hold of these 19 alts drew down about 80-90% in 2022. This panel is mostly flat with at most 60% gross, so I pre-register a 25% maximum drawdown. Not a duplicate: the in-pipeline HL panels condition on price only (HyperliquidAltPanelCapitulationAbsorption4H, the HL capitulation-close transfer that ended underpowered on one crash cluster) or on a BTC residual (HL idiosyncratic down-shock, BTC-hedged). This is the first HL test whose trigger requires a direct forced-deleveraging marker, and the first that reads that marker on another venue.