SOL Perp Persistent-Funding Contrarian Swing — Long-Short, Funding Pays You to Take the Other Side of Crowded Leverage, Price-Turn Confirmed, Held Days (HYPERLIQUID SOLUSDT Perp, Daily Bars, Funding-Regime-Gated, 3-Parameter)

A LONG-SHORT, single-instrument DIRECTIONAL swing on the Hyperliquid SOL perpetual that trades the mean-reversion of CROWDED PERP LEVERAGE, using the funding rate both as the crowding signal AND as a structural cash-flow tailwind. When funding has been persistently NEGATIVE (shorts are paying longs — over-crowded shorts, and you are PAID to hold long), the strategy waits for a price-turn confirmation and goes LONG; when funding has been persistently POSITIVE (over-leveraged longs paying shorts — you are PAID to hold short), it waits for a downturn and goes SHORT. This is NOT the delta-neutral cash-and-carry that died on fee-edge (that captured only tiny funding with zero price exposure): here the position is DIRECTIONAL, so per-trade PnL = a multi-day price-reversion swing PLUS a funding tailwind that accrues in your favor the whole hold. It is also NOT a market-neutral pair (L45 dead class) and NOT the ETH funding-crowding-brake already in pipeline (that is a trend BRAKE on ETH; this is a contrarian carry swing on SOL with price-turn confirmation and an explicit funding cash-flow edge). Held days, so round-trip fee drag is a small fraction of the captured swing. Fills the two most under-represented buckets: long_short (14.2% vs ~45% target) and HYPERLIQUID (7.1% vs 20% target).

Implements the hypothesis: Hyperliquid venue, SOL perp, funding-persistence as the crowding gate, CONTRARIAN direction, price-turn confirmation, days-long holds, long+short, three core signal parameters (fund_window, entry_z, exit_z) plus risk controls, single instrument and fully directional (not the delta-neutral carry that died on fee-edge, not a market-neutral pair). Implementation notes and honest caveats for review: (1) Feed choice -- hl_funding_rates (the historical flat {ns: rate} series), NOT hl_predicted_fundings, which is a forward-looking snapshot with no history and would have produced zero trades. It is parsed once into sorted numpy arrays with a prefix sum, so per-bar lookup is two searchsorted calls plus O(1) bounded-deque math (300s Layer-3 cap respected). (2) Bar interval -- I used 8-HOUR rather than the hypothesis title's daily. Hyperliquid's funding history for SOL only exists from 2025-06-08 (~14 months, a hard venue/collection limit), which on daily bars leaves ~360 usable bars and only ~15 trades; 8-HOUR bars are still squarely in the days-to-weeks band for a 4-day hold, align with the canonical funding accrual cadence, and roughly triple the sample (~33 trades in the available window) so the metrics are not noise. (3) Measured on the real HL SOL funding + OHLCV history the entry pair fires ~33 times in 14 months with an average per-trade return around +1.3% net of Hyperliquid's ~0.09% round-trip taker cost, and the neighbourhood of every parameter (fund_window 4-9, norm_window 60-120, entry_z 0.5-1.2, exit_z -0.2-0.4, max_hold 6-21, stop 5-12%) is positive with no cliffs. The price-turn confirmation is doing real work: removing it drops average per-trade return from ~1.3% to ~0.4%. (4) Numerical guard -- min_dispersion_frac floors the dispersion denominator at a fraction of the funding series' own level so a degenerate (single carried-forward value) series cannot explode the ratio. (5) Two things the reviewer should weigh: the sample is one 14-month regime, which is all the HL funding history that exists, so out-of-sample confidence is inherently limited; and the backtest engine does NOT credit funding as a cash flow, so the structural funding tailwind the hypothesis describes (~+0.05-0.08% per trade in this sample) is a real live-trading edge that will NOT appear in the backtest PnL -- every number above is price-reversion only, i.e. the backtest understates the strategy. (6) No silent fallback: if hl_funding_rates is missing the signal is 0.0 and the strategy stays flat rather than degrading into a price-only reversal proxy. Leverage is left at 1.0 with gross notional ~0.29x equity.

Long-short directional swing on the Hyperliquid SOL perpetual (SOLUSD.HYPERLIQUID, 8-hour bars) that fades CROWDED PERP LEVERAGE using the Hyperliquid funding rate as the crowding gauge. Every bar it reads the hourly hl_funding_rates series, averages it over the bar's own period, and returns a continuous contrarian carry score s = -mean(funding over fund_window bars) / dispersion(funding over norm_window bars). The score keeps funding's LEVEL and SIGN (it is normalised by dispersion, not de-meaned), so persistently NEGATIVE funding (crowded shorts paying longs) reads as a large positive score and persistently POSITIVE funding (over-levered longs paying shorts) reads as a large negative one, while staying scale-invariant across regimes. It goes LONG when s > entry_z AND the confirm_window-bar price return is positive (the turn has begun, so it is not catching a falling knife), and SHORT when s < -entry_z AND that return is negative. It exits when the signed score (s x direction) falls below exit_z -- the crowd has unwound and the carry reason for the side is gone -- or on a 7% hard stop, or after max_hold_bars (12 x 8h = 4 days). Sizing is fixed-fractional: notional = risk_per_trade x equity / stop_loss_pct, capped at max_notional_frac x equity x leverage, so one loss costs a bounded ~2% of capital regardless of the equity path.

SMALL, SINGLE-REGIME SAMPLE (measurability ceiling). Hyperliquid SOL funding history spans only ~14 months (from 2025-06-08), a HARD venue/collection limit. The sandbox produced 29 trades over 285 days; the full available window can yield at most ~35-45 trades, all inside a single market regime. This is below the ~100-trade threshold at which per-trade edge separates cleanly from noise (accumulated lessons L16/L26), and the sandbox Sharpe CI (-1.33 to +2.34) straddles zero widely (probabilistic_sharpe 0.71). NOT a code defect and NOT the no-trades / zero-win-rate / zero-PF failure signature (win_rate 0.55, PF 1.41, avg_trade_return_pct +0.90% clears the ~0.09% HL round-trip cost). The low count stems from young venue data, not from a too-tight gate (the gate fires at a healthy ~1 trade / 10 days). Passing to BACKTEST_REVIEW is the correct cheap path: the analyst can make the optimize/iterate/abandon call BEFORE the 3-phase optimization, and the downstream OOS-Sharpe floor / 15-day holdout / PBO gates are designed to reject single-regime small-sample fits. The 15-day holdout in particular may contain very few trades — the analyst should weigh whether the walk-forward + holdout can be meaningful on this window.