Handling Missing User Data in DAC8 Reports

Category: Troubleshooting Last Updated: 2026-02-12

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Overview

One of the most common practical challenges in DAC8 compliance is dealing with incomplete user data. Reportable Users may not have provided their Tax Identification Number (TIN), complete address, date of birth, or self-certification of tax residence. Since DAC8 reports require specific data elements to be present, missing information can block submission or result in non-compliant filings. This article provides a structured approach to identifying, resolving, and documenting missing data situations.

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Problem: User Has Not Provided a TIN

Cause

Users may have registered on the platform before DAC8 requirements took effect, or the onboarding process may not have made the TIN field mandatory. In some cases, users may be reluctant to share their TIN.

Fix

1. Send a direct request. Contact the user through your standard communication channels (email, in-app notification, or both) and explain that their TIN is required for regulatory reporting purposes.
2. Set a reasonable deadline. Give the user a clear timeframe to respond (for example, 30 days).
3. Follow up. If the user does not respond to the initial request, send at least one documented follow-up communication.
4. Document everything. Record the date, channel, and content of each request and any responses received. This documentation is essential for demonstrating reasonable efforts.
5. Assess the outcome. If the TIN is still missing after reasonable efforts, consult your jurisdiction's specific rules on whether submission without a TIN is permitted and under what conditions.

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Problem: Incomplete or Missing Address

Cause

Address data may be partially collected (for example, a city without a postal code), stored in a non-standard format, or missing entirely for users who registered with minimal information.

Fix

1. Identify the specific gaps. Compare the address data you hold against the DAC8 schema requirements, which typically include address line, city, country code, and potentially postal code.
2. Request the missing components. Contact the user to request the specific address fields that are missing.
3. Cross-reference available data. If you have partial address information, check whether other data points (such as IP address geolocation or payment method details) can help confirm the country of residence. Note that such indirect indicators should support, not replace, a formal self-certification.
4. Use structured address formats. When collecting address data, use structured fields (street, city, postal code, country) rather than a single free-text field to minimize formatting issues at report generation time.

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Problem: Self-Certification Not Obtained

Cause

DAC8 requires RCASPs to obtain a self-certification from each Reportable User confirming their tax residence jurisdiction(s). Users who onboarded before the requirement may not have completed this step. Some users may also ignore requests to complete the certification.

Fix

1. Implement a self-certification workflow. If you do not already have one, create a process for collecting self-certifications (either during onboarding for new users or as a retroactive campaign for existing users).
2. Restrict certain features if necessary. Some RCASPs choose to restrict account functionality (such as withdrawals) until self-certification is completed. Check whether this approach is permitted and proportionate under your jurisdiction's rules.
3. Request and follow up. As with TINs, send an initial request and at least one follow-up, documenting all attempts.
4. Apply indicia rules. If a self-certification cannot be obtained, you may need to fall back on other indicators (such as address on file or jurisdiction of the identity document) to determine the likely tax residence. Be aware that these fallback methods may have specific rules under DAC8 or related due diligence procedures.

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Problem: Date of Birth is Missing

Cause

Date of birth is typically a required field for individual Reportable Users in DAC8 reports. It may be missing if the platform did not collect it during registration or if the data was lost during system migrations.

Fix

1. Request the information directly. Ask the user to provide or confirm their date of birth.
2. Check identity verification records. If your platform has performed KYC (Know Your Customer) checks, the date of birth may already be available in your identity verification records even if it was not stored in the user's profile.
3. Update your onboarding flow. Ensure that date of birth is a mandatory field for all new registrations going forward.

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Follow-Up Procedures: A Structured Approach

When dealing with any missing data element, a consistent follow-up process helps demonstrate compliance with the reasonable efforts standard:

1. Initial notification (Day 0). Send a clear, specific request identifying exactly what information is needed and why.
2. First follow-up (Day 14-30). If no response, send a reminder with the same details.
3. Final notice (Day 45-60). Send a final reminder, noting any consequences of non-response (such as account restrictions, if applicable).
4. Close the loop. After the final notice, if the data is still missing, document the outcome and proceed according to your jurisdiction's rules.

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Documenting Reasonable Efforts

Maintaining a clear audit trail is essential. For each user with missing data, record:

• The specific data element(s) that are missing.
• The date and method of each outreach attempt.
• Any responses received from the user.
• The final outcome (data collected, or data still missing with explanation).

This documentation may be requested by tax authorities during an audit and serves as evidence that your organization took the required steps.

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Disclaimer

This article provides general operational guidance. The specific requirements for reasonable efforts, self-certification, and handling of missing data may vary by EU Member State. Consult the relevant national tax authority's guidance and, where appropriate, seek professional legal or tax advice.