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# Collateral & Accounts

Everything you trade on Hash Power Perps is backed by collateral held in a
shared **CollateralVault**. This page explains how collateral gets in and
out, how your balance is used, and why it is shared with the Futures market.

---

## The shared collateral vault

Perps does **not** custody tokens itself. Collateral lives in a separate
`CollateralVault` contract that is shared across the Hash Power venues
(Perps and Futures). The DEX only asks the vault to move balances internally
when trades, fees, funding, or liquidations settle.

```mermaid
flowchart LR
    Wallet["Your wallet<br/>ERC-20 collateral"]
    Vault["CollateralVault<br/>receipt balance"]
    Markets["Perps / Futures"]

    Wallet -->|"deposit(amount)"| Vault
    Vault -->|"withdraw(amount)"| Wallet
    Vault <-->|"internalTransfer<br/>PnL · fees · funding"| Markets
```

When you `deposit`, the vault pulls your ERC-20 collateral and credits you an
equal **receipt balance**. `HashPowerPerpsDEX.balanceOf(you)` simply reads
that vault balance.

## Depositing

Call the vault directly:

| Function                                          | Use                                                        |
| ------------------------------------------------- | ---------------------------------------------------------- |
| `deposit(amount)`                                 | Pull `amount` of collateral from you, credit your balance  |
| `depositForPermit(recipient, amount, deadline, v, r, s)` | Approve + deposit in one transaction (ERC-2612 permit) |
| `depositFor(recipient, amount)`                   | Deposit on behalf of another account                       |

Before `deposit`, approve the vault to spend your collateral (or use
`depositForPermit` to combine approval and deposit in a single transaction).

## Withdrawing

```
withdraw(amount)
```

Withdrawals burn your receipt balance and return the underlying token. A
withdrawal **reverts if it would breach your portfolio margin** — you can
only take out collateral that is not backing an open position or resting
order (your *free* / excess margin).

## One balance, two venues (portfolio margin)

Your vault balance is a **single pool of margin** that backs positions on
both Perps and Futures at the same time. Margin requirements are computed at
the **portfolio** level by the `PortfolioMarginEngine`, so offsetting
exposure across venues can reduce the total margin you need, and a
withdrawal is checked against your combined requirement.

Practical consequences:

- Depositing once funds trading on both venues.
- A loss (or owed funding) on one venue reduces the collateral available to
  the other.
- Your Perps liquidation threshold depends on your **whole** portfolio, not
  just your Perps position.

## Your balance components

At any time your vault balance is conceptually split into:

| Component            | Meaning                                                         |
| -------------------- | -------------------------------------------------------------- |
| Initial Margin (IM)  | Locked to **open / increase** exposure                         |
| Maintenance Margin (MM) | The floor below which you become liquidatable               |
| Order margin         | Extra IM your resting (unmatched) orders add, after netting them against your positions |
| Free / excess margin | Withdrawable collateral above all requirements                 |

Useful views:

- `balanceOf(user)` — total vault balance.
- `computePortfolioIM(user)` / `computePortfolioMM(user)` on the margin engine — current IM / MM across all products.
- `orderMarginOf(user)` on the margin engine — collateral reserved by resting orders. Portfolio-wide, not per-venue: the engine nets each market's resting-order delta into your total before stressing it, so an order that only moves you toward flat reserves nothing. The figure moves with the price; it is not a fixed amount set when you placed the order.
- `getUnrealizedPnl(user)` — mark-to-market PnL on the open position.
- `getPendingFunding(user)` — unsettled funding (positive = you owe).

## The insurance fund

The vault holds a protocol-owned **insurance fund** account
(`INSURANCE_FUND_ADDR`). It is the counterparty ledger for:

- **Fees** — taker/maker fees are paid into it (see [Fees](./06.Fees.md)).
- **Funding** — funding payments flow to/from it.
- **PnL & bad debt** — realized PnL settles against it; if a liquidated
  account can't cover its loss, the shortfall is **absorbed by the insurance
  fund** (never taken from other users). See
  [Margin & Liquidation](./05.Margin-and-Liquidation.md).

---

## Read next

- [Trading Guide](./03.Trading-Guide.md) — place your first order.
- [Margin & Liquidation](./05.Margin-and-Liquidation.md) — keep your account healthy.