⚠︎ Risk warning: leveraged derivatives on unregulated platforms — you can lose everything you deposit. Not investment advice.
Mark price and funding on Lighter
Formulas verified against Lighter's official docs on 2026-09-29. Live funding across venues is on the funding screener, which divides Lighter's published 8-hour rate by eight.
Two prices matter on Lighter. The index price is the underlying's spot price, which Lighter takes from "a combination of oracles (Chainlink, Stork, Pyth)". The mark price is the contract's fair price, and it is the one that decides liquidations, stop triggers and unrealised PnL.
How the mark price is built
The docs define it as the median of three numbers:
- The impact price: the midpoint of the average fill prices for a market sell and a market buy of an "impact notional" of 500 USDC ÷ the market's initial margin fraction. On a 10× market (10% initial margin) that is a $5,000 order.
- Index plus premium: the index price plus an 8-minute moving average of (impact price − index), with the gap clamped to ±0.5% of the index.
- Other exchanges: the median of mark prices "from different centralized exchanges".
Lighter explains why its own book is in there directly: because the mark price decides liquidations, "the mark price should reflect as much as possible the impact price, so that the execution of liquidations should happen close to mark price." The median means one of the three can go wrong without moving the mark. On real-world-asset markets the other-exchange leg is replaced by Lighter's RWA pricing, described on RWA markets.
Funding in one paragraph
Funding is paid every hour, "fully peer-to-peer with no fees taken by the exchange": longs pay shorts when the rate is positive, and the reverse when it is negative. Once a minute, at a random time, Lighter samples a premium from the impact bid and ask against the index; each hour it averages the 60 samples, pulls the result toward a 0.01% interest rate within a ±0.05% band, caps it at ±4%, and divides by eight. That puts the hard cap at 0.5% per hour, and a quiet market at 0.01% ÷ 8 = 0.00125% per hour. The premium is scaled by 1 on crypto, ½ on RWAs and 1/100 on pre-IPO and pre-markets. Your payment is −position × index price × funding rate. The full formula and parameters are on the Lighter fees page.
FAQ
Why does my liquidation price move when nothing traded?
Because the mark price follows the index and other exchanges as well as Lighter's book, and your account value uses the mark.
Is the rate on Lighter's API hourly?
Lighter's funding-rates endpoint reports an eight-hour figure; this site divides it by eight before comparing venues. That was checked against the endpoint's own Hyperliquid rows and is logged on the corrections page.
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