Hyperliquid has published the fee structure for its outcome tokens, the assets that underpin prediction market-style trading on the platform, in a sign that a mainnet launch is getting closer.

Prediction markets have become one of crypto's fastest-growing areas, with trading volume surging more than 300% in 2025 to $63.5 billion, and Hyperliquid is building the infrastructure to compete with incumbents such as Kalshi and Polymarket.

The key detail in the structure is that opening a position costs nothing. Fees only apply when closing or settling a trade. The document outlines six scenarios covering minting, trading, burning and settlement.

Traders using Hyperliquid's "aligned quote tokens" get better rates, with taker fees 20% lower and maker rebates 50% higher than standard. The full fee formula has been published for developers.

The broader significance is that HIP-4, the upgrade introducing outcome tokens, would let users trade binary contracts on real-world events alongside Hyperliquid's existing perpetuals and spot positions in a single account as it looks to compete with platforms like Polymarket, which said earlier this week that perpetual trading is "coming soon."

Hyperliquid's previous upgrade, HIP-3, which opened permissionless perpetuals to developers, has grown to more than 35% of all platform trading volume since its introduction in October 2025.

Outcome tokens are currently on testnet only. No mainnet date has been confirmed.