Collateral
A firm funds its margin account in USDC or EURC before trading: every position locks its initial margin out of that balance, and no position opens unfunded. The contract holds the collateral and never lends or re-pledges it, the protection called non-rehypothecation. CRX takes no custody. The margin engine runs the margin on every position, and the firm hears from it only when the account needs funding.
Eligible collateral
Two assets are eligible: USDC, a dollar stablecoin, and EURC, a euro stablecoin. A position runs in one of them, chosen at the trade: the collateral posts in it, and the settlement pays in it. The asset is matched across both sides — when the taker posts USDC, the maker posts USDC, and a EURC position is EURC on both sides.
What is the margin account?
The firm's available trading balance. A deposit credits it, the funds stay withdrawable, and one margin account funds every position the firm opens. Profit and loss flows through it: gains credit the account, and obligations draw on it.
Withdrawal releases only the available balance. The contract verifies the margin the open book requires before it releases anything.
Where is the margin account?
In a smart contract on a public chain. The margin account and each position's locked margin are balances the contract itself holds. The code that moves them is public, and every record is immutable. The account is not held at CRX: the funds never touch its balance sheet.
What still runs if every CRX service goes offline — settlement, the co-signed close, and a direct withdraw — is covered in the FAQ (~4 min).
The two states of collateral
Collateral is always in one of two states:
| State | What it is | What it holds |
|---|---|---|
| Margin account | The firm's available balance | USDC and EURC, free to withdraw or margin |
| Locked initial margin | The buffer behind one position | Initial margin only, for that one position |
Locked margin returns to the margin account when its position ends.
Next: The Margin Engine (~3 min). What locks at the bind, how profit and loss settles, and what happens when a call goes unmet.