PearnPayout math
How principal is protected and how the pot is split. Source of truth is PayoutMath.sol.
rate is yoctoNEAR per 1 stNEAR (1e24 scale). It only rises: the oracle ignores any lower reading.
At bet time
principal = staked × rate / 1e24 // the bet's NEAR value
weight = principal × (closeTime − now)A stale, lower rate only under-counts your own principal; the difference ends up in the pot, never in anyone else's pocket.
At settlement (rate R)
reserve = ceil(Σ principal × 1e24 / R) // stNEAR needed to give everyone their NEAR back
pot = Σ staked − reserve + sponsored // all the yield, plus sponsorsClaims
| Case | You receive (stNEAR) |
|---|---|
| Lost | floor(principal × 1e24 / R) |
| Won | refund + pot × weight / W_winning |
| Invalid, or nobody on the winning side | refund + pot × weight / W_all |
| Nobody bet at all | sponsors get their sponsorship back |
Refunds and shares round down, the reserve rounds up, and the rate never falls. So Σ refunds ≤ reserve and Σ shares ≤ pot: the contract can never owe more than it holds. A fuzz test (testFuzz_noLossAndSolvent) checks exactly that.
Example
Ten thousand NEAR in a market for 30 days at 4.5% APY earns about 37 NEAR. With bettors split 50/50, winners make about 0.74% on their principal in a month, twice normal staking, and losers lose nothing. Sponsored pots and long markets make it worth more.
The app's projection uses a TypeScript port of the same math (apps/web/lib/payout.ts), tested against the Solidity unit-test numbers.