> ## Documentation Index
> Fetch the complete documentation index at: https://docs.marks.finance/llms.txt
> Use this file to discover all available pages before exploring further.

# Add to a Hedge

> Grow an open Hedge by adding notional, keeping the same maturity.

Because you hold at most one open Hedge per market and side, you grow a position by adding to the existing Hedge instead of opening a second one. The added notional nets into the same position at a size-weighted **blended rate** and inherits the original `maturity_at`. Adding is asynchronous and fills the same way an open does.

<Info>
  Trying to open a second Hedge on a market and side you already hold returns `409 hedge_exists`. Add to it instead.
</Info>

## Request

You add to a Hedge by market and side - Marks resolves your open Hedge on that side server-side.

| Field                     | Type   | Required | Description                                             |
| ------------------------- | ------ | -------- | ------------------------------------------------------- |
| `market`                  | string | No       | Defaults to `USDTNGN`.                                  |
| `side`                    | string | Yes      | `buy` or `sell` - the side of the open Hedge to add to. |
| `additional_notional_usd` | number | Yes      | Notional to add, greater than 0.                        |

<Info>
  Pass an `Idempotency-Key` so the add is safe to retry. See [API Conventions](/guides/api-conventions#idempotency).
</Info>

```bash theme={null}
curl -X POST "$BASE_URL/hedges/add" \
  -H "Authorization: Bearer $MARKS_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{"market":"USDTNGN","side":"sell","additional_notional_usd":50000}'
```

Returns `404 no_open_hedge` if you don't have an open Hedge on that side - open one instead.

## The response

The `hedge_id` is unchanged - the top-up nets into it. `collateral_usdc` is the extra locked for the added notional, `new_notional_usd` is the position's total after the add, and `maturity_at` is unchanged: the top-up inherits the original maturity.

<Tip>
  To shrink a position instead of growing it, see [Reduce a Hedge](/guides/reduce-a-hedge) - the mirror operation. To change a Hedge's maturity, you can't add: settle the current Hedge and open a new one at the tenor you want.
</Tip>