# V (Market data request)

The FIX message **`V` (Market Data)** is used to request market data for a specific [currency pair](/docs/guides/exchange-fix-api/market-data-fix-api/supported-fix-messages/fix-application-level-messages/currency-pairs), and initiates the process of receiving market data updates.
It allows clients to subscribe to one of the following event types:
- Order Book updates (full snapshots only) = **`W` (Market Data - Snapshot / Full Refresh)**
- Trades Executions = **`X` (Market Data - Incremental Refresh)**

:::note
Market data subscription should be requested with a single message, containing all requested currency pairs and update types (BID, ASK, Trade execution).

Sending a new **`V` (Market Data Request)** request will override previous subscriptions.
:::

| Tag                                 |           | Name                        | Type           | Required                                        | Description                                                                                                                                                                          |
| ----------------------------------- | --------- | --------------------------- | -------------- | ----------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **262**                             |           | `MDReqID`                   | `String`       | **yes**                                         | Unique identifier of the subscription request.                                                                                                                                       |
| **263**                             |           | `SubscriptionRequestType`   | `Char`         | **yes**                                         | Subscription request type. <br/><br/>Supported values: <br/> <ul><li> `1` - Subscribe</li><li>`2` - Unsubscribe</li></ul>                                                            |
| **264**                             |           | `MarketDepth`               | `Int`          | **yes**                                         | Maximum depth of the market for Order Book Snapshot. <br/><br/> `0` means the highest supported limit for order book.                                                                |
| **267**                             |           | `NoMDEntryTypes`            | `NumInGroup`   | **yes**                                         | Number of the listed entry types.                                                                                                                                                    |
| ↳                                   | **269**   | `MDEntryType`               | `Char`         | **yes**                                         | Type of the requested subscription. <br/><br/>Supported values: <br/><ul><li> `0` - BID</li><li>`1` - ASK</li><li>`2` - Trade execution</li></ul>                                    |
| **146**                             |           | `NoRelatedSym`              | `NumInGroup`   | **yes**                                         | Number of the [currency pairs](/docs/guides/exchange-fix-api/market-data-fix-api/supported-fix-messages/fix-application-level-messages/currency-pairs) requested for subscription.   |
| ↳                                   | **55**    | `Symbol`                    | `String`       | **yes**                                         | [Currency pair](/docs/guides/exchange-fix-api/market-data-fix-api/supported-fix-messages/fix-application-level-messages/currency-pairs).                                             |

Depending on the subscription, Revolut FIX Gateway replies with Market Data messages taking one of the two forms:
- [**`W` (Market Data - Full Refresh)**](/docs/guides/exchange-fix-api/market-data-fix-api/supported-fix-messages/fix-application-level-messages/message-w-full-refresh) - snapshot of the order book for the specific currency pair, containing requested depth.
- [**`X` (Market Data - Incremental Refresh)**](/docs/guides/exchange-fix-api/market-data-fix-api/supported-fix-messages/fix-application-level-messages/message-x-incremental-refresh) - used to transmit trade executions only.

For more details, see [`FIX 4.4 : Market Data Request <V> message` in the FIX 4.4 documentation](https://www.onixs.biz/fix-dictionary/4.4/msgType_V_86.html).