What Is USDH on Hyperliquid? Mainnet HIP-4 Uses USDC

The short answer

Current Hyperliquid mainnet HIP-4 markets use USDC as their quote and settlement asset. USDH can still appear in legacy testnet fixtures and historical integration material, but it should not be presented as the current mainnet settlement token.

On August 3, 2026, Purrdict verified the current public data and repository fixtures:

• all eight active mainnet outcomeMeta rows returned quoteToken: USDC;
• current settlement and fee-token handling uses USDC;
• only retired legacy testnet fixtures retained USDH labels.

That history explains why a trader or developer may still encounter both tickers in old screenshots, fixtures, or articles even though the current mainnet path is USDC.

Quote token and settlement record are separate fields

A quote token labels the unit used to describe an active order book. If a side is offered at 0.64, the quote field tells an integration how to label that price and cost while the market is open.

A settlement fill records what happened after the outcome resolved. HIP-4 winning fills use dir: Settlement with a price of 1; losing fills use a price of 0. The fill’s asset or fee-token fields show how the resulting account credit is represented.

The quote label and final credit remain separate API concepts even when both currently name USDC. Treating fields as interchangeable can still produce a UI that labels balances incorrectly, calculates fees in the wrong unit, or carries a legacy testnet token into mainnet.

What the active API showed

The public mainnet info endpoint accepts an outcomeMeta request. A recurring market in the August 3 snapshot had the following relevant shape:

{
  "name": "Recurring",
  "description": "class:priceBinary|underlying:BTC|expiry:20260804-0600|targetPrice:62809|period:1d",
  "sideSpecs": [{ "name": "Yes" }, { "name": "No" }],
  "quoteToken": "USDC"
}

The same response contained active daily BTC, ETH, SOL, and HYPE price binaries plus a BTC price-bucket question. Live inventory changes as rounds expire, so the response should be queried again rather than treated as a permanent list.

What current settlement records show

After an outcome resolves, account history exposes settlement fills. The current fields are:

dir: Settlement
px: 1.0 or 0.0
feeToken: USDC

The winning and losing sides settle atomically in the observed flow. USDC is credited automatically; there is no normal “claim winnings” transaction. The public settledOutcome info request can also expose the winning fraction and recorded oracle-price detail for a settled outcome.

The feeToken name can be confusing because integrations may use it while computing or displaying the realized account change. The safe implementation is to read the actual fill and balance data rather than infer the asset from a historical fixture.

What this means for traders

Before entering a HIP-4 market:

1. Read the network indicator and active market metadata.
2. Review the quoted order cost and fee in the live order preview.
3. Treat a side price as an executable order-book price, not a guaranteed probability.
4. After resolution, inspect the settlement fill and resulting balance asset.
5. Do not assume an old article or screenshot reflects the current asset rails.

An outright outcome purchase still has a bounded ordinary loss equal to its purchase cost. Asset-label accuracy does not remove spread, slippage, liquidity, specification, operational, or protocol risk.

What this means for HIP-4 developers

An integration should keep at least four concepts separate:

• market quote metadata from outcomeMeta;
• side price and size from the order book or fill;
• fee asset and amount from the signed order preview and fill;
• settlement credit from settlement fills and account balances.

Do not hard-code one token across mainnet and testnet. Store token identifiers alongside values, format them only at the presentation layer, and preserve the raw response for debugging.

The same caution applies to HIP-4 identifiers. A #N API coin, +N balance token, and integer order asset are related representations of one side, but they are not interchangeable strings. Purrdict’s open-source @purrdict/hip4 package provides tested mapping helpers.

Where does USDH fit?

USDH and USDC are distinct asset labels and should be treated as distinct tokens wherever the API exposes them. In the HIP-4 context reviewed here, USDH belongs to legacy testnet data rather than current mainnet quote and settlement records. A one-dollar target or similar ticker does not make contracts, issuers, reserves, bridges, or account representations interchangeable.

This article deliberately does not make an unsupported claim about reserve composition or redemption terms. Anyone holding a stable-value asset should verify the current issuer documentation, contract address, liquidity, and redemption path rather than relying only on a ticker.

Why older HIP-4 articles conflict

HIP-4 has evolved from testnet experiments into curated mainnet markets, while public documentation remains incomplete. Old fixture data, UI labels, and integration assumptions can survive long after the live response changes.

Purrdict therefore dates protocol observations and separates:

• curated HIP-4 markets on mainnet;
• permissionless template-based deployment on testnet;
• synthetic Purrdict parlays and vaults on HyperEVM Testnet;
• current mainnet records from legacy testnet fixtures.

For the full current model, read HIP-4 prediction markets on Hyperliquid and the deeper prediction-markets-on-Hyperliquid guide.

Bottom line

Current mainnet HIP-4 markets expose quoteToken: USDC, and current settlement fills use feeToken: USDC. USDH references in this area are legacy testnet artifacts, not evidence that today’s mainnet markets settle in USDH. Read the live fields, keep asset labels attached to their values, and do not let historical fixtures override current network data.