---
title: "US Options Open Interest"
method: GET
path: "/v1/data/us-equity-opt/open-interest/{identifier}"
tags: ["us-equity-opt-daily"]
---

# US Options Open Interest

`GET /v1/data/us-equity-opt/open-interest/{identifier}`

The U.S. Options Open Interest dataset provides daily open interest information for U.S. equity and index options, derived from Options Price Reporting Authority (OPRA) open interest publications. The dataset consolidates open interest across all U.S. equity options exchanges, delivering contract-level visibility into the number of outstanding option positions at the end of each trading day. Open interest values are provided per option contract, enabling analysis of market participation, liquidity concentration, positioning trends, and risk exposure across strikes, expirations, and option types.

 For more details, please refer to the dataset documentation: [US Options Open Interest Guide](https://us-options-market-data-docs.s3.us-east-1.amazonaws.com/algoseek.US.OPRA.Options.Open.Interest.pdf).

<details>
<summary>**Advanced Filtering**</summary>

You can provide one or multiple filter expressions based on the dataset's columns to narrow down the results. For example, `StartDate.gt=2023-01-01&StartDate.lt=2023-12-31`, `Ticker=AAPL`. 

Please refer to the <a href="https://algoseek.com/docs/rest-api/tutorial/advanced-filtering">Advanced Filtering Guide</a> for the extensive reference.
</details>

## Path parameters

- `identifier` string, required — Dataset's security identifier

## Query parameters

- `period` string, nullable — A string representing the time period for which to retrieve data. The format and accepted values depend on the dataset. If not provided, data for all available periods will be returned.
- `sort` string, nullable — Sorting criteria for the results. Provide a column name with optional prefix '+' for ascending order, or prefix with '-' for descending order. Multiple sorting fields may be supported depending on the dataset. If sort prefix is not provided, the ascending order is applied.
- `columns` string, nullable — A comma-separated list of columns to include in the response. Use this parameter to select only specific fields from the dataset. If not provided, all available columns will be returned.
- `offset` integer — Number of records to skip before returning results. To be used with the `limit` parameter for pagination. If not provided, defaults to 0.
- `limit` integer — Maximum number of records to return. Default and maximum values depend on the response format; see `format_limits` in the schema for details.
- `response_format` 'json' | 'csv' | 'csv_gzip' — Note the lowercase which is used for the consistency with other projects and tools

## Response `200`

JSON, CSV file, or gzip-compressed CSV file, depending on the value of `response_format` query parameter

- USOptionsOpenInterestDataOut
  - `data` USOptionsOpenInterestDataDetailsOut[], required
    - `TradeDate` string, date, nullable — The trading day
    - `EventDateTime` string, date-time, nullable — Event timestamp (EST) with a millisecond resolution
    - `Ticker` string, nullable — Symbol name
    - `CallPut` string, nullable — Option contract class: "C" for Call or "P" for Put
    - `Strike` number, nullable — A fixed price for buying or selling an underlying security
    - `ExpirationDate` string, date, nullable — Expiration date of the option contract
    - `OpenInterest` integer, nullable — The total number of options contracts held by market participants for the previous trading day
  - `pagination` PaginationDetailsOut, required
    - `offset` integer — The number of records skipped to fetch the current page
    - `limit` integer, required — The maximum number of records in the current page
    - `next_offset` integer, nullable — The number of records to skip to fetch the next page

## Other responses

- `403` — Forbidden
- `422` — Validation Error
- `429` — Request rejected because the identity or team exceeded a configured monthly or per-minute usage quota. When available, the response includes rate-limit headers describing the current quota.

---

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