Pricing
How the contract quotes UP and DOWN on every trade, and why there's always a price.
ROPES doesn't match buyers with sellers. RopeMarket is the market maker: it quotes both sides itself, from the Hyperliquid mark, at the moment each trade lands.
The formula
fair(UP) = Φ( ln(S / K) ÷ (σ · √τ) )
| Symbol | Meaning |
|---|---|
S | the latest Hyperliquid mark, carried in with the trade |
K | the strike: the open of Hyperliquid's 1-minute candle for this round |
τ | seconds left until the bell |
σ | HYPE's volatility of ln(price) per √second |
Φ | the standard normal CDF |
This is the fair price of a binary option: the probability that HYPE finishes above the strike, given where it is now and how much time is left. A DOWN share is worth 1 − fair(UP).
The quote
| UP | DOWN | |
|---|---|---|
| Buy at | fair + 1% | 1 − (fair − 1%) |
| Sell (BAIL) at | fair − 1% | 1 − (fair + 1%) |
- The half-spread is 1% (
halfSpread = 10000, in units of 1e6). - It doubles in the last 10 seconds (
lateSecs = 10), when prices swing fastest. - Quotes are clamped to [0, 1]. A side that has lost all its value sells for 0.
- The game won't enter a side priced above 0.90. At that price you risk the whole stack to make 11%.
Volatility
σ is measured from the last ~65 one-minute Hyperliquid closes, floored at 0.04% a minute so a quiet hour can't price the next minute as a certainty. The keeper re-measures it every hour and pushes it on-chain when it moves more than 10%. The contract only accepts σ between 1e13 and 5e15 (wad per √second), roughly a 0.008% to 3.9% one-minute move.
How it's computed on-chain
fairUpAt(s, k, tau, sigma) is a public pure function, so anyone can check a quote:
ln(S/K)uses Solady'slnWad.√τuses Solady'ssqrt.Φuses the Abramowitz & Stegun 7.1.26 approximation oferf(max error 1.5e-7, below one probability unit of 1e-6) with Solady'sexpWad.
The test suite checks Φ against reference values (Φ(1) = 0.841345, Φ(2) = 0.977250, Φ(0.5) = 0.691462) to within 2 units of 1e-6.
Why this needs Elysium
A one-minute binary moves fast: one $0.01 tick on HYPE can move fair value by 10 points near the bell. Pricing it fairly means re-quoting on every trade, which is only practical on a chain with ~115 ms blocks and gas around 0.1 gwei.