US500 Weekly

# US500 Weekly A three-rung ladder on the S&P 500 index, settled from the **Pyth `Equity.Index.US500/USD` feed**. Three independent weekly lanes expire at the 16:00 New York cash close on Monday, Wednesday, and Friday. Each lane rolls to the same weekday one week later. The outcome markets are hedgeable with `xyz:SP500`, but settlement reads the Pyth cash index rather than that perp's trades. ## At a glance | | | |---|---| | Question | Will the S&P 500 be above the strike at the 16:00 ET expiry? | | Settlement measure | [Pyth](/price-feeds/pyth) `Equity.Index.US500/USD` confidence-weighted TWAP | | Strike | `round(TWAP, 35)` with offsets `−75 / 0 / +75` | | Rungs | 3 per expiry — down, middle, and up | | Cadence | Monday, Wednesday, and Friday at 16:00 `America/New_York` | | UTC time | 20:00 during EDT; 21:00 during EST | | Lifetime | 168 hours; each lane is a full week | | Settlement window | The 90 seconds ending exactly at expiry | | Payout | Yes if TWAP is strictly above the strike; equality pays No | | Concurrency | 9 markets — 3 rungs × 3 weekly lanes | | Deploy cost | 9 registrations/week — 3 on each roll day | ## Three lanes, not one rotating expiry Monday's market runs Monday to Monday, Wednesday's Wednesday to Wednesday, and Friday's Friday to Friday. The three dates are live together. This makes every rung a five-session market and lets one wing size mean the same thing on all three lanes. The cadence is defined in `America/New_York`, so the expiry stays at the cash close through daylight-saving changes. Only its displayed UTC hour moves. ## Strike identity The offsets are fixed and have distinct residues on the 35-point grid: | Rung | Offset | Residue mod 35 | |---|---:|---:| | Down | −75 | 30 | | Middle | 0 | 0 | | Up | +75 | 5 | Those residues let the deployer identify sibling rungs sharing an expiry. The ±75 wings are about 0.67 standard deviations over five sessions using the 60-day volatility measurement behind the live slate, placing them near the 25th and 75th percentiles at mint. ## Naming and resolution The immutable on-chain terms name `perp:xyz:SP500`, “the Pyth US500 index price”, `seconds:90`, the threshold, and the exact expiry. The chain renders names in this form: ```text US500 above {strike} at {YYYYMMDD-HHMM}? ``` Settlement uses the confidence-weighted computation documented on the [Pyth feed page](/price-feeds/pyth#how-the-window-resolves). There is no closeness band: above pays Yes, while equality and below pay No. Missing evidence can void at 0.5 after retries, but the window never slides. ## Notes for makers The hedge carries basis. `xyz:SP500` is a perp; the settlement value is Pyth's cash index. The index also stops moving outside its trading session while the outcome books remain open. Size both risks explicitly. All three Mon/Wed/Fri lanes are live on mainnet. Read current strikes from the markets API or chain metadata rather than extrapolating from prior ladders.