> For the complete documentation index, see [llms.txt](https://docs.aeralend.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aeralend.app/how-it-works/bcook-collateral.md).

# bCOOK as collateral

**bCOOK is staked COOK.** You get it by staking COOK with [BakeYourStake](https://stake.cookiescan.io), and it accrues value as the stake pool earns. It is the only collateral Aera Core accepts.

## Your staking rewards continue

This is the reason Aera exists in this shape. When you lock bCOOK:

* Aera **holds the token**. It does not unstake it, redeem it, or route it anywhere.
* The stake pool does not know or care that it is locked.
* Rewards accrue as they always did — as a rising bCOOK rate, not as a payment.

So you keep the staking position **and** have COOK to use. Aera pays you nothing for locking collateral, and takes nothing from what the stake pool pays.

{% hint style="info" %}
Do not add the staking yield and the borrow cost together as if they offset. They come from different places, and the borrow cost is charged on your debt while the staking yield accrues on your collateral. Those are different bases.
{% endhint %}

## How it is valued

Three steps, in this order:

```
      2,000 bCOOK
    × the gross stake-pool rate          e.g. 1.0400 COOK per bCOOK
    × (1 − the pool's withdrawal fee)    e.g. 2%  →  1.0192 effective
    = 2,038.40 COOK                      what it is worth to redeem
    × 95%   (the 5% haircut)
    = 1,936.48 COOK                      what Aera counts
```

**The withdrawal fee comes off first.** The gross rate is what the pool says one bCOOK is worth; the effective rate is what you would actually receive on redemption. Valuing collateral at the gross rate would overstate every position on the book by exactly that fee.

The remaining 5% haircut is a buffer against the rate moving between the moment a position becomes unhealthy and the moment a liquidator acts. It applies before both the 55% borrowing limit and the 65% liquidation threshold — so one bCOOK backs borrowing of about 52% of its redeemable value.

## Unlocking

With no debt, all of it, whenever you like.

With debt, up to the point where your health factor would reach 1.00. The Unlock sheet's **MAX** computes that from the same preview the program uses to accept or reject the transaction, so it cannot offer you an amount that then fails.

{% content-ref url="/pages/ctOgnD8L9ahjXMtH8UoU" %}
[Health and liquidation](/how-it-works/health-and-liquidation.md)
{% endcontent-ref %}


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