# Vault Account

The **Vault Account** is a struct used for accounting in the Fraxlend Pair:

```solidity
struct VaultAccount {
    uint128 amount;
    uint128 shares;
}
```

The **Vault Account** contains two elements:

1. **`amount`** - represents a total amount
2. **`shares`** - represents claims against the amount

#### Lending Accounting

In lending, **`amount`** represents the total amount of assets deposited and the interest accrued.

When lenders deposit assets, the amount of assets deposited increases **`amount`,** the **`shares`** value is also increased by an amount such that the ratio between **`amount`**/**`shares`** remains unchanged.

When interest is accrued, **`amount`** is increased and **`shares`** remains the same.  Each lender's share of the underlying assets are measured in shares.

When lenders remove liquidity, they redeem shares for the underlying asset.  The **`shares`** amount will be decreased by the number of shares redeemed, the **`amount`** will be decreased such that the ratio between **`amount`**/**`shares`** remains unchanged.

**Borrow Accounting**

In borrowing, **`amount`** represents the total amount of assets borrowed and the interest accrued.

When borrowers receive assets, the number of tokens received increases **`amount`,** the **`shares`** value is also increased by an amount such that the ratio between **`amount`**/**`shares`** remains unchanged.

When interest is accrued, **`amount`** is increased and **`shares`** remains the same.  Each borrower's debt is measured in shares.

When borrower's repay debt, **`amount`** is decremented by the amount of assets returned, **`shares`** is decreased by an amount such that the ratio of **`amount`**/**`shares`** remain unchanged.  An individual borrowers shares balance is decremented by this number of shares.