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

# Data Normalization

Each service provider returns financial data with slightly different conventions — signage, status names, and category labels. Meld normalizes these into a single consistent shape so your code does not need provider-specific branches. This page is for developers consuming Meld's APIs who want to understand the normalized values and the rules behind them. Raw provider responses are still available in the `serviceProviderDetails` field on every endpoint and in the Activity Log.

## Balance signage

Balance signage is generally **positive** for all account types — including loan, mortgage, and credit accounts, where a positive balance indicates the amount the customer owes.

## Transaction signage

Service providers use different signage for deposits vs. withdrawals. Meld standardizes to:

* **Positive** — money has moved **out** of the account. Includes withdrawals and debits.
* **Negative** — money has moved **into** the account. Includes deposits.

## Investment types

For both investment holdings and investment transactions, Meld normalizes the investment `type` in the response.

* **Investment holdings:** `STOCK`, `MUTUALFUND`, `CASH`, `OTHER`, `REALESTATE`, `ETF`, `DERIVATIVE`, `DIGITALASSET`.
* **Investment transactions:** `SELL`, `BUY`, `CANCEL`, `CASH`, `OTHER`, `TRANSFER`.

## Transaction status

Transactions have one of the following statuses:

* **Pending** — All transactions start as `PENDING`. A pending transaction has been approved but not yet fully processed.
* **Posted** — `PENDING` transactions move to `POSTED` within a few days, typically one to five business days, with a rare two-week maximum.
* **Expired** — On rare occasions, `PENDING` transactions are cancelled and stop appearing in provider responses. When this occurs, Meld marks them `EXPIRED`.

<Tip>
  When updating transaction data, fetch the last 14 days to capture status and amount changes. After two weeks, transactions almost never change.
</Tip>

## Transaction categories

While providers group transactions into their own categories, Meld also normalizes transaction categories across providers.

<Note>
  For the complete provider-to-Meld category mapping, refer to the [account transactions reference](/docs/bank-linking/bank-linking-quickstart/bank-linking-products/account-transactions) and the [Bank Linking API reference](/api-reference/bank-linking).
</Note>