---
title: "US Equities ASID Lookup"
method: GET
path: "/v1/data/us-equity-ref/secid-chains-lookup"
tags: ["us-equity-ref-sec-master-lookups"]
---

# US Equities ASID Lookup

`GET /v1/data/us-equity-ref/secid-chains-lookup`

The U.S. Equities ASID Lookup dataset covers all listed and delisted U.S. equity securities, including common stocks, ETFs, ETNs, ADRs, preferred stocks, warrants, and related instruments, from 2007 to the present. The dataset captures ticker symbols and their effective date ranges, enabling accurate tracking of securities across symbol changes over time. This dataset is designed to support continuous pricing and reference history construction in cases where a security’s internal identifier changes. algoseek assigns each security a SecId, which remains stable across name and ticker changes but may change following certain security restructurings (for example, reclassification events). To preserve continuity across such identifier changes, algoseek introduces a higher-level persistent identifier, ASID (algoseek Security ID). An ASID remains constant for the entire economic life of a security and links together all related SecIds associated with that security over time. The ASID Lookup dataset therefore provides the authoritative mapping needed to chain SecIds and maintain uninterrupted historical time series across complex lifecycle events.

 For more details, please refer to the dataset documentation: [US Equities ASID Lookup Guide](https://us-equity-reference-docs.s3.us-east-1.amazonaws.com/algoseek.US.Equity.SecId.Chains.Lookup.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>

## Query parameters

- `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

- USEquitiesASIDLookupDataOut
  - `data` USEquitiesASIDLookupDataDetailsOut[], required
    - `ASID` integer, nullable — A unique identifier for a security
    - `Ticker` string, nullable — Symbol name
    - `StartDate` string, date, nullable — The start date
    - `EndDate` string, date, nullable — The end date
  - `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.

---

[API](https://skmtc.net/algoseek/apis/datasets-api.md) · [All operations](https://skmtc.net/algoseek/apis/datasets-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/algoseek/datasets-api/revisions/1c983de099e2/schema)