When to use
Binary markets only cover two outcomes. For questions with 3+ exclusive
outcomes — e.g. “Who wins the Premier League?” with Arsenal / Chelsea /
Draw / Other — PredictStreet uses a neg-risk market backed by the
NegRiskAdapter contract.
Neg-risk lets you trade each outcome independently as a separate
binary YES/NO, but guarantees collateral efficiency via
convertPositions: holding the full set of NO tokens is equivalent
to holding 1 USDC, which can be converted back atomically.
Differences from binary
Different verifyingContract. An EIP-712 order signed for the
binary exchange will fail signature validation on a neg-risk market.
Always match verifyingContract to the market type.
Outcome indexing
For a 4-outcome market (["Arsenal", "Chelsea", "Draw", "Other"]),
outcomes are "0", "1", "2", "3". Each outcome has its own
YES and NO tokens.
convertPositions
The neg-risk invariant: holding NO across all outcomes except one
is equivalent to holding 1 USDC. convertPositions collapses that
basket into collateral atomically.
The request uses a dual-signature flow (user + backend).
Resolution
The oracle settles each outcome independently against the same
conditionId. At resolution, reportPayouts is called with a
payout array where exactly one outcome is 1 and the rest are 0.
Current limitation (testnet): the automated multi-source
oracle-service does not yet propose outcomes for neg-risk markets
directly — it flows outcomes through PredictStreetOracle only.
Neg-risk market resolution on testnet is driven by the
admin-controlled path against NegRiskAdapter. The 2h challenge
window and bond mechanics still apply at the PredictStreetOracle
level for the underlying condition. Automated neg-risk proposal
support is on the oracle-service roadmap.
