---
title: Clearing and Settlement
description: Understand how trades change account positions and collateral, how self-trades are prevented, and how resolved markets settle.
---

Each account holds its own balances and positions. Trades update the account's net position and collateral requirement.

## Accounts and Collateral

Orders and trades always belong to an account. The account determines where the resulting position and collateral are recorded.

Use a transfer to move available cash between your accounts. A transfer does not move positions or open orders.

## Offset a Position

Positions are netted within an account and market. An opposite-side trade reduces the existing position.

| Action | Net YES position |
| --- | ---: |
| Buy 10 contracts | `+10` |
| Sell 4 contracts | `+6` |
| Sell 6 more contracts | `0` |

Reducing a position may release collateral. The exact change depends on the account's other positions and the market relationship.

An opposite-side order offsets a position only after it trades with another participant. UDX prevents your own orders from trading with each other.

## Prevent Self-Trades

Set `self_trade_prevention_type` on each order to choose which order gives way if the new order would match one of your resting orders.

If you omit `self_trade_prevention_type`, UDX uses `placed`. The incoming order is canceled when it would match your resting order, and the resting order stays open.

| Value | Behavior |
| --- | --- |
| `placed` | Cancels the incoming order when it would self-trade. The resting order stays open. |
| `resting` | Cancels the conflicting resting order and allows the incoming order to continue matching. |

Self-trade prevention cannot be disabled. See [Place an Order](/api-reference/orders/createorder) for the request field.

## Resolution and Settlement

Resolution determines whether a market finishes YES or NO. Settlement then applies that result to the account's remaining position:

- a winning contract pays $1.00;
- a losing contract pays $0.00; and
- the position closes after settlement.