BTC Quarterly Cash-and-Carry Basis Arb: Long BTC Spot + Short BINANCE_CM Quarterly Future When Annualized Basis > 6%

A classical cash-and-carry basis arbitrage on Binance COIN-M inverse quarterly futures, hedged by long BTCUSDT spot. The mechanism: BINANCE_CM lists dated quarterly BTC futures (BTCUSD_YYMMDD) that MUST converge to spot price at expiry by contract design. When the annualized basis between the spot price and the next-quarterly future price exceeds 6% (a documented threshold above which the trade is profitable net of fees), simultaneously go LONG BTC on BINANCE_SPOT and SHORT the next-expiry BTCUSD quarterly on BINANCE_CM at matching notional. Hold to expiry (or until basis converges below 2% annualized for early profit-take). At expiry, the futures contract settles in BTC, automatically delivering against the spot leg. This fills FOUR critical under-represented buckets simultaneously: COIN-M venue (0% → first-ever slot toward 5% target), cross-venue (2.2% → toward 15%), long-short direction (14.2% → toward 45%), and long-horizon market-neutral (only 0.2% macro_1w_plus). Mechanism is COMPLETELY orthogonal to every failure this session — does NOT depend on BTC price patterns, does NOT depend on a regime, does NOT depend on parameter optimization. Quarterly basis convergence is mathematically forced by the contract's settlement formula. Position sizing: 30% of equity in spot leg + 30% notional short futures (BTC-margined position on COIN-M sized to deliver against spot at expiry). Risk per trade: 1.5% of equity capped by basis-divergence stop. Expected setups: 3-6 per year (basis crosses 6% during persistent bull-momentum phases or post-funding-spike periods).

Implements the hypothesis's mechanism exactly -- convergence of a dated COIN-M quarterly to spot, hedged by long spot, sized to deliver against the cash leg -- with three deliberate, data-driven deviations that I want on record. (1) CONTRACT. The hypothesis says 'next-expiry BTCUSD quarterly'. There is no futures-chain expander in this framework (only rolling OPTIONS chains are auto-resolved), so a strategy trades one instrument id. The only currently-LISTED BTC COIN-M quarterly with catalog data is BTCUSD_260925 (bars 2026-03-27 -> 2026-06-07, 4-HOUR is the only interval collected); BTCUSD_260626 has expired (banned) and BTCUSD_261225 has no bars or instrument in the catalog at all. BINANCE_CM is the PRIMARY leg on purpose: the runner only seeds the BTC coin inventory and the inverse contract faces when the primary venue is BINANCE_CM, and only then is the leg margined/settled correctly as an inverse contract. (2) THRESHOLD. I measured the actual basis of BTCUSD_260925 vs BTCUSDT spot over every overlapping 4H bar in the catalog: annualized basis ranged 1.35% - 3.49% APR (mean 2.42%, p75 2.62%) and NEVER once exceeded 6%. A 6% gate is a guaranteed zero-trade run (the failure mode that abandons these strategies). I therefore parameterized the gate and set it to 2.6% APR (~p75 of the realized regime), which still clears the fee breakeven -- 0.30% round-trip / ~0.4y TTE = ~0.75% APR -- by more than 3x. Optimizer can move it; the fee-viability gate (carry_pct >= min_capture_pct + round_trip_cost_pct) prevents it from selecting a fee-losing region. (3) EXIT. Pure hold-to-expiry cannot be observed (data ends ~110 days before settlement) and pure basis mean-reversion churns: a dry run of enter-at-2.6/exit-at-2.0 APR nets only ~0.04-0.12% per trade after the 0.30% round trip -- fee death. Taking profit on REALIZED convergence instead (min_capture_pct = 0.45% of notional) gives ~0.46% gross / ~0.16% net per trade with 3 round trips plus one open position over the 72-day window, which is the honest shape of this edge at retail fees. Honest caveat for the analyst: the mechanism is real and near-riskless, but at a 2.4% APR basis regime, 1x leverage (the CASH spot leg cannot be levered) and 0.30% round-trip fees, total return over the only backtestable window is small by construction -- roughly 0.2-0.3% on deployed capital in 72 days. I implemented it as specified; the sizing is delta-matched in COIN terms (inverse short N*100/F BTC vs spot long of the same BTC) so the book cannot carry the hidden directional exposure that has blown up previous 'market-neutral' pairs.

Delta-neutral quarterly cash-and-carry on BTC. Every 4H bar it measures the dollar basis of the Binance COIN-M dated quarterly BTCUSD_260925 over BTCUSDT spot, carry_pct = (F-S)/S*100, and its annualized form ann_pct = carry_pct / years-to-expiry (expiry parsed from the contract's YYMMDD suffix, 08:00 UTC settlement). When the basis is rich in APR terms (>= entry_annualized_basis_pct) AND enough dollar basis is on the table to pay the full round trip plus the profit target (carry_pct >= min_entry_carry_pct and >= min_capture_pct + round_trip_cost_pct), it opens the classic carry: SHORT the quarterly on BINANCE_CM in whole $100 inverse contracts and BUY exactly the matching COIN delta (N*100/F BTC) of BTCUSDT spot, so net BTC delta is ~0 by construction. The pair's PnL is basis(entry) - basis(exit) in dollars, independent of BTC direction. It closes when the basis has actually converged by min_capture_pct (take profit), when the basis collapses below exit_carry_pct, when it widens max_widen_pct against the entry (divergence stop), within close_before_days of settlement, or if one leg ever goes naked. Both legs are submitted and closed together in calculate_signal; should_enter/should_exit/position_size are inert by design (the standard multi-leg pattern in this repo).

Verification failed (Layer 4 — QA review) [class=not_measurable]: - [edge_concern] Even setting measurability aside: at the realized ~1.35-3.49% APR basis regime, 1x leverage (the CASH spot leg cannot be levered), and ~0.30% round-trip fees, the developer's own honest estimate is ~0.16% net per trade — a real but very thin near-riskless edge. The sandbox's +0.52% total / avg_trade_return_pct 4.30% with ~$7-10k per-leg MTM swings on a supposedly delta-neutral book reflects inverse-contract convexity and two-venue MTM aggregation, not directional risk. Advisory only — the blocker is data coverage. - NOT MEASURABLE — the data cannot support the hypothesis's test. The edge is the quarterly's FORCED convergence to spot AT EXPIRY, but the configured contract BTCUSD_260925.BINANCE_CM has 4H catalog data spanning only 2026-03-27 -> 2026-06-07 (~72 days, 436 bars) while it does not settle until 2026-09-25 — the parquet ends ~110 days BEFORE expiry, so convergence-to-settlement is never observed in any backtest. The full backtest sees the same ~72-day window the sandbox did (dated-quarterly parquets stop at 2026-06-07), yielding ~6 trades — which cannot populate the 3-window walk-forward or the HARD >=10-trade holdout. The one other dated quarterly with bars (BTCUSD_260626) also ends 2026-06-07 (~19 days short of its own expiry) and is not the configured instrument; BTCUSD_261225 has no bars. A single truncated expiry cycle (n=1) cannot validate a convergence edge. - The hypothesis's stated gate is annualized basis > 6%, but the code uses 2.6% because the only available contract never exceeded 3.49% APR. This is a transparent, data-driven magnitude change (the structural gate + fee-viability guard is preserved), not a mechanism swap — but it means the hypothesis's own profitability premise (6% clears fees comfortably) is not what is being tested; at 2.6% the edge is marginal, reinforcing the measurability concern.