BCDA Historical Data error

[Margaret Stone]

We are a new MSSP ACO that began Performance Year 2026 on January 1, 2026. As a new ACO using BCDA for the first time this performance year, we expected to receive historical claims data for our full attributed population going back at least 2-3 years when running bulk data export jobs.

We are observing significantly lower than expected claims volume for periods prior to January 2026. Our 2026 claims appear to be flowing correctly, but pre-2026 months show substantially lower institutional, professional, and pharmacy claim counts than what would be expected for our attributed population size.

 

We attempted to run a historical bulk data job using the /Group/all endpoint with a _since parameter set to approximately two years prior. This returned the following error:

"Error sending Bulk Data Kickoff: Request Failed. Response from server: 404 / NotFound / Not Found. Operation Outcome Message: failed to start job; attribution file not found for given _since parameter."

We then ran a job with _since set to approximately four months prior (covering back to January 1, 2026), which completed successfully and returned data. This confirms our API credentials and connection are functioning correctly.

 

Is there any known issue with historical claims availability for new MSSP ACOs onboarding in PY2026 that may affect the expected volume we receive?

What is the recommended path to retrieve the full historical claims record for our currently attributed population?

[Beneficiary Claims Data API (BCDA) Community]

Hi Margaret, 

Thank you for reaching out! To retrieve the full historical claims record for your currently attributed population, we recommend making an export request without using the _since parameter. The error you are seeing is expected; as a new ACO, your oldest BCDA attribution data would be from 2026. Please see our documentation on filtering data, including the _since parameter, on our website. 

If this does not address your issue with the low volume of claims, please let us know and provide your 5-digit ACO ID.

Thank you, 

The BCDA team

[Margaret Stone]

Thank you for the response! 

We are now receiving what I hope are our historical claims.

We are concerned about that time estimate for loading this data. Can you help  clarify what full historical load means? 

Based on the volume, it seems like we are getting data from a lot further back then the past 2 years. Is there an option to modify the lookback period? or can you confirm what the historical lookback period is?  

Apologies if this was sent twice. 

[Margaret Stone]

Thank you! That seemed to help us with our issue. We're now retrieving what seems to be historical claims, but we seem to be processing a huge amount of data. It seems like we may be receiving more than 2 years of claims history. Can you confirm what the lookback of the historical claims will be? and if there is a way to reduce it to be only 2 years?  

On Friday, May 1, 2026 at 2:10:04 PM UTC-5 Beneficiary Claims Data API (BCDA) Community wrote:

[Beneficiary Claims Data API (BCDA) Community]

Hi Margaret, 

Glad to hear you are able to access your data now! At this time, the Shared Savings Program does not have a limit to ACO lookback data availability for currently aligned beneficiaries, so you may be receiving data as far back as 2014 for some beneficiaries. While the upcoming version of BCDA will include more advanced filtering by service date, it is not offered for v2. Once you have completed your historical download, fields such as ExplanationOfBenefit.meta.lastUpdated or ExplanationOfBenefit.billablePeriod can be used to filter the data down to the last two years' claims. 

Please let us know if you have any further questions!

Thank you, 

The BCDA team