How a quote is built
An underlying stock reference, a spread for trading costs, and a signed inventory adjustment. Try how they form an OPmode price.
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center = −3.0 bps; half-spread = 5.0 base + 0.4 size + 2.0 confidence + 0.0 session = 7.4 bps
The live parameters
OPmode normalizes Pyth's underlying stock or ETF price once by the issuer multiplier, assuming 1 USDC equals 1 USD. The half-spread adds base, size, confidence cost and any session premium. Inventory shifts the center of both prices: excess stock lowers the bid and ask, while scarce stock raises both. Either price can cross the reference. All ten pools use these parameters:
| Term | Value on every OPmode market |
|---|---|
| Base | 0.05% (5 bps) |
| Size | 0.04% (4 bps) per 1,000 USDC of notional |
| Confidence cost | Twice the feed's relative confidence interval, added to each half-spread |
| Session | 0; the engine supports a session premium, and these pools set it to zero |
| Inventory center shift | up to ±0.15% (15 bps), reached at 10% from the inventory target |
At the order limits the size term is small: 0.4 bps on a 100 USDC order, 0.08 bps on 20 USDC. The engine works in integer parts per million: ask prices round up, bid prices round down, and the fee rounds up. The 5 bps fee is separate from the spread.
The target balances stock and USDC value using the underlying reference, after reserving outputs for outstanding quotes. A trade cannot worsen a stock-value weight outside 25–75%. NVDAx allows up to 100 USDC per order and 500 per fixed 60-second window; each other OPmode pool allows 20 and 100. These windows reset in fixed intervals rather than measuring a rolling minute.
Source data must be no more than five seconds old when a new quote is issued. Active markets target two-second reference updates; published values expire within 20 seconds of their source observation. Quotes last at most ten seconds, with at least five seconds left for review when issued. See Reference prices for the checks and current trust model.
Read more
The written explanation lives on How pricing works and in the litepaper. For the session term see Sessions and market hours, and for inventory see Pools, inventory and skew.