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Technical Notice

OTC Transparency API Changes

March 08, 2021

On Friday, February 19, 2021, FINRA introduced a new Historical Data API via the FINRA API Developer Center (  The OTC Transparency Weekly Summary will be the first dataset available via the Historical Data API and will be named WeeklySummaryHistoric.  This change is designed to facilitate those API users who are downloading large amounts of historical data, defined as data older than one year. The fields returned in the WeeklySummaryHistoric dataset are the same fields that are returned in the existing WeeklySummary dataset.

The Historical API provides limited filtering capability consistent with the goal of supporting the download of large datasets.  The WeeklySummaryHistoric dataset supports filtering on the following fields:

  • weekStartDate
  • historicalWeek
  • historicalMonth

In addition to one of the above fields, users can also use the tierIdentifier field to further refine their results; no other fields can be included in a request filter.

The historical data will continue to be available in both the weeklySummary and weeklySummaryHistoric datasets until April 30, 2021. Beginning on Monday, May 3, 2021, a rolling four years of data will be available in the weeklySummaryHistoric dataset. A rolling 12 months of data will be available via the weeklySummary dataset.

FINRA also launched asynchronous API requests on February 19, 2021. API users will have the option of requesting asynchronous access or synchronous access to a dataset when making API requests. The Asynchronous API is strongly recommended when requesting large volumes of data in an API request (including when accessing the weeklySummaryHistoric dataset) and will resolve time-out errors that some API users may have experienced.

Additional changes include:

  1. Support for the use of the sortFields parameter with appropriate restrictions to protect the integrity of the API platform.
  2. Deprecation of the equityShortInterest dataset which will be replaced by the equityShortInterestStandardized dataset that has been modified to conform to an industry wide push to standardize short interest data. The equityShortInterest dataset will not be published after April 30, 2021.

Finally, please refamiliarize yourself with the API platform usage restrictions. Specifically, we have added further restrictions around the use of the offset parameter when paging through large datasets that may be a breaking change for some implementations. We have also identified appropriate use guidelines for using the API platform that are essential to the overall integrity of the API platform.

Please refer to the Q1 Update Summary on the FINRA API Developer Center for more information and for links to details about each change described in this notice.

Questions can be forwarded to FINRA API Support.