How Mark Index works

Mark Index is a trading interface on top of Hyperliquid, made for wallets that live on Robinhood Chain. It has no contract of its own that holds money: everything you deposit sits in your own Hyperliquid account.

What happens where

• Prices, order book, matching, margin, liquidations: Hyperliquid, read and written through its public API.
• Stock, index, metal, energy and FX markets: deployed on Hyperliquid by trade.xyz (HIP-3). Mark Index lists them, it does not create them.
• Deposits: Relay (relay.link) takes ETH or USDG on Robinhood Chain and credits USDC to the same address on Hyperliquid.
• Withdrawals: Hyperliquid's own bridge, in USDC on Arbitrum, for a flat $1.

Enabling trading

The first time, your wallet signs up to three messages. None costs gas and none moves money.

1. Trading key. The browser makes a new key and your wallet approves it as a Hyperliquid API wallet named "Mark Index". It can place and cancel orders and change leverage. Hyperliquid does not let it withdraw or transfer. The key stays in this browser's storage; clearing it, or approving a new one, retires it.
2. Builder fee. You approve a maximum fee of 0.05% for Mark Index. Each order then states the fee it pays, which is never above that.
3. One balance (optional). Hyperliquid keeps stock markets in their own margin pool. Turning on its unified account lets the same USDC back crypto and stocks.

Fees

Hyperliquid charges its own trading fee (0.045% taker, 0.015% maker at the base tier). Mark Index adds a builder fee on each fill, set by how much $MKX the trading wallet holds on Robinhood Chain:

• Open: no token, 0.05%
• Holder: 100,000 $MKX or more, 0.035%
• Pro: 1,000,000 $MKX or more, 0.02%
• Prime: 10,000,000 $MKX or more, 0.01%

The balance is read from the chain before each order. Nothing is staked or locked. The builder address is not set yet, so orders currently carry no Mark Index fee.

Risks

• Perpetuals with leverage can be liquidated quickly. You can lose your whole margin.
• Stock perps track a price through an oracle. They are not shares, carry no dividend or vote, and can move when the stock market is closed.
• Mark Index depends on Hyperliquid, trade.xyz and Relay staying up and honest. None of them is run by Mark Index.
• Not offered to residents of the United States or of sanctioned countries.