Rich Bids

Detector: for three strikes K− < K < K+ of the same expiration+right, option fair value is convex in strike, so mid(K) can never exceed the strike-weighted interpolation of the neighbor mids ("Fair"). A BID at/above Fair × 1.15 violates that no-arbitrage bound — the signature of a single aggressive buyer, not a market. Guards: clean quotes on the center and both neighbors (ask > bid > 0), bid ≥ $0.10, bid size ≥ 5, DTE 1–100, neighbor strike gaps ≤ 30% of spot. Open interest is deliberately NOT required — a brand-new buyer on a zero-OI strike is exactly the target (OI 0 is highlighted as fresh interest). ROC conventions: ROC/d% = bid premium / collateral / DTE with collateral = strike×100 for puts (cash-secured) and spot×100 for calls (covered proxy) — the far-OTM board convention; rows only appear when ROC/d ≥ 0.5%. MarginROC/d (more-columns) uses the naked Reg-T margin instead (20%/10% formula, unlevered). Freshness: "First seen" comes from a state file keyed ticker|exp|strike|right; a key that disappears is kept for 120 min (scan-to-scan flicker doesn't reset it) then pruned, so the same bid returning hours later shows as NEW again and re-alerts. Rows show only the CURRENT scan — a rich bid that vanished is gone from the board immediately.