Parimutuel Pool Markets

Parimutuel markets are Strike's pool-based prediction market format. They sit alongside the FBA orderbook: orderbook markets are best for actively traded binary outcomes, while parimutuel pools are best for multi-choice events, longer-running questions, and markets where users want simple buy-and-hold exposure without managing limit orders.

What They Are

A parimutuel market has 2–8 outcomes. Traders choose an outcome and buy into that outcome's pool with USDT. There is no orderbook and no selling/cashout in V1 — positions are internal, non-transferable claims on the final pool.

When the market resolves, the winning side receives:

1. their own winning principal back, plus

2. a proportional share of the losing outcome pools.

Losing outcomes pay nothing. If a market is invalid or cancelled, users can refund their principal.

Orderbook vs. Parimutuel

Feature	FBA Orderbook Markets	Parimutuel Pool Markets
Best for	Liquid binary markets and active trading	Multi-choice events and simple directional exposure
Outcomes	Binary UP/DOWN or YES/NO	2–8 named outcomes
Pricing	Limit-order price discovery, $0.01–$0.99 ticks	Pool-implied probabilities from current liquidity
Execution	Periodic batch auctions at a uniform clearing price	Immediate buy into the selected outcome pool
Position management	Can sell before expiry through the orderbook	Buy-and-hold until claim/refund
Resolution	Pyth, AI, or admin fallback depending on market	Admin, AI, or Pyth with admin fallback
Payout	Winning positions redeem fixed value per lot	Winners split losing pools pro-rata

Both systems are fully collateralized with USDT and settle through on-chain contracts.

Market Timing

Parimutuel V2 separates the betting cutoff from the event timestamp:

• Trading close time — the last time users can buy into the pools.

• Resolution time — the event/reference timestamp used by the resolver.

This matters for markets where betting should close before the event concludes. For example, a sports market can stop accepting buys at kickoff but resolve after full time.

The contracts enforce resolutionTime >= tradingCloseTime. Buying and pool closing use tradingCloseTime; admin, AI, and Pyth resolution paths use resolutionTime.

Resolution Modes

Admin

The market creator/admin resolves to the winning outcome or marks the market invalid. This is useful for controlled internal markets and events that require human judgment.

AI

The Parimutuel AI resolver sends a configured prompt to the Flap AI Oracle. The AI proposes the winning outcome, then a challenge/finality flow allows review before finalization. If the AI path fails or is challenged, the market can fall back to admin resolution.

Pyth

The Parimutuel Pyth resolver uses a Pyth price feed at the market's resolutionTime and maps price thresholds to outcomes. This supports price-range markets such as "Where will BTC/USD be at 12:00 UTC?" with multiple buckets.

Pool Pricing

Strike uses bounded curve presets to turn pool balances into displayed probabilities and projected payouts. The default recommended curve is the independent-log preset with L = 40,000 USDT; a more conservative L = 100,000 USDT preset is also supported.

The frontend shows:

• each outcome's current pool size,

• implied probability,

• projected payout for a new buy,

• total pool size,

• user's positions and claim/refund state.

Lifecycle

1. Created — outcomes, resolver mode, trading close time, resolution time, fee, and curve are configured.

2. Open — users buy into outcome pools until tradingCloseTime.

3. Closed — no more buys; the market waits for resolutionTime.

4. Resolving — AI/Pyth/admin resolution is requested or submitted.

5. Resolved — winning outcome is final; winners can claim.

6. Invalid/Cancelled — users can refund principal.

Contracts

The parimutuel stack is separate from the orderbook stack:

• ParimutuelFactory — creates markets and coordinates lifecycle/resolution.

• ParimutuelPoolManager — handles buys, pool accounting, and curve math.

• ParimutuelVault — holds USDT collateral for pool markets.

• ParimutuelRedemption — claims winning payouts and refunds invalid markets.

• ParimutuelAIResolver — Flap AI Oracle integration and challenge/finality flow.

• ParimutuelPythResolver — Pyth price-threshold resolution.

See Deployments for live addresses.