Hyperliquid ETH Daily Time-Series Momentum, LONG/SHORT (Single-Instrument HYPERLIQUID Perp, Pure OHLCV, Flip-Via-Flat, Fixed-Fractional Sizing — Direct ETH Analog of the PROMOTED HL BTC Daily TS-Momentum LS, Applying the ONE Validated HL Mechanism to the Other Clean Major on the Strong-Walk-Forward Daily Cadence, Pre-Registered Strong-WF Acceptance, Fills Long-Short + HL Venue, Tail-Safe, Low-Parameter)

A LONG-SHORT, SINGLE-INSTRUMENT, DAILY time-series (absolute) momentum strategy on ETHUSD.HYPERLIQUID — the direct instrument-analog of the PROMOTED HL BTC daily TS-momentum LS (Sharpe 0.68, walk-forward OOS 2.52, PF 1.59). It is grounded in the now-resolved HL cadence map: the ONLY validatable HL cadences are DAILY (~3yr, for edges that survive the thin 15-day holdout via a STRONG walk-forward) and 4H (~1.3yr, for turnover ideas); 1H (~7mo) and 15-min (~2mo) are data-walled (stop probing). The promoted BTC book proved that TS-momentum is the mechanism that DOES validate on HL daily — it survived the thin holdout precisely because its walk-forward OOS was strong (2.52). This hypothesis tests whether that single validated mechanism PORTS to the other confirmed-clean major (HL ETH sizes 64.5%; SOL is data-poisoned; BTC/ETH are the only clean instruments). It is deliberately the strong-WF daily route, NOT a sparsity-prone construction: TS-momentum on daily produced enough trades + strong WF on BTC, so the same on ETH is the legitimate HL-daily play (unlike the daily breakout/reversal that died on holdout sparsity). It is DISTINCT from: the failed HL ETH daily DONCHIAN BREAKOUT (a channel breakout with 1.05x whipsaw geometry — TS-momentum is a smoother sign-of-trailing-return signal, a different mechanism); the failed HL ETH daily REVERSAL (momentum is the opposite mechanism); and the pending HL 4H reversion books (different cadence + mechanism). It fills the dominant direction gap (long_only 85.9% vs <=55%) and under-weight HL venue (7.5% vs >=20%). HONEST CAVEAT / asset-selectivity: ETH trends weaker than BTC (its breakout had no edge), so this is a genuine test of whether TS-momentum extracts ETH's weaker-but-present daily trend; the construction is identical to the promoted BTC book so any difference is the asset, not the code. Bug-avoiding: pure OHLCV, ONE fixed-fractional size per entry, NO dynamic resizing, leverage 1.0, dual flat guard, flip-via-flat (clean LS path — HL BTC LS sized 97%, ETH expected similar). PRE-REGISTERED ACCEPTANCE: (1) STRONG-WF — like the BTC sibling, the edge must survive HL daily's thin holdout via a non-overfit walk-forward (IS/OOS ratio < 3, OOS Sharpe positive); if ETH momentum is too weak (breakeven/weak WF OOS), ABANDON — do NOT force/iterate (ETH momentum weakness is structural, not tunable, per the breakout finding). (2) SIZING — avg_position_pct ~95-100%, no impossible single-day returns; else escalate. Daily 4H depth not relevant — HL ETH daily has ~3yr. Low parameter count (momentum lookback, optional EMA confirm, ATR stop).