Is there a legal requirement to keep unsubscribed email addresses for four years under CAN-SPAM?
Michael Ko
Co-founder & CEO, Suped
Published 25 Apr 2025
Updated 19 Aug 2025
7 min read
I recently heard a claim that businesses are legally required to retain unsubscribed email addresses for four years under the CAN-SPAM Act, supposedly due to the statute of limitations on complaints. Having worked in the email space for nearly two decades, this was a new one for me, and it immediately raised a red flag. I couldn't find any direct reference to such a requirement within the CAN-SPAM legislation itself.
The CAN-SPAM Act, which stands for "Controlling the Assault of Non-Solicited Pornography and Marketing" Act, sets the rules for commercial email in the United States. While it does outline specific requirements for handling unsubscribe requests, a four-year retention period for unsubscribed addresses is not one of them. This article will clarify what CAN-SPAM actually mandates regarding opt-outs and explore why such a misunderstanding might arise.
CAN-SPAM's actual unsubscribe requirements
The core of CAN-SPAM's unsubscribe rules revolves around providing a clear and easy way for recipients to opt out and honoring those requests promptly. It's designed to give recipients control over the commercial emails they receive.
Opt-out mechanism: Every commercial email must include a clear and conspicuous way for recipients to opt out of receiving future emails. This can be a return email address or another Internet-based mechanism, such as an unsubscribe link. The link should allow for a one-click unsubscribe for easier compliance, especially with the latest Gmail and Yahoo requirements.
Timely processing: You must honor opt-out requests within 10 business days. During this period, you cannot send any further commercial emails to that address. Best practice, however, dictates processing these requests much faster, ideally immediately.
Mechanism duration: The unsubscribe mechanism must remain active for at least 30 days after the email is sent.
There are no provisions within CAN-SPAM that mandate storing unsubscribed email addresses for any specific duration beyond ensuring the unsubscribe mechanism functions for 30 days and honoring the opt-out within 10 business days. Once an individual has opted out, you are legally obligated to stop sending them commercial messages, and their opt-out status does not expire.
The origin of the four-year claim
So, if CAN-SPAM doesn't require a four-year retention, where might this idea come from? It's likely a misinterpretation of legal advice, possibly related to general record-keeping practices or statutes of limitations in other areas of law, not directly tied to the CAN-SPAM Act itself.
Businesses often maintain data for various reasons, such as tax purposes, contractual obligations, or to defend against potential legal claims. A four-year retention period might align with a general statute of limitations for certain types of civil actions, and a legal team might recommend keeping records of unsubscribe requests to prove compliance if a complaint were ever filed. However, this is a company-specific best practice (or a blocklist avoidance strategy), not a direct CAN-SPAM mandate.
Instead of deleting unsubscribed contacts, most email service providers (ESPs) and businesses move them to a suppression list. This list ensures that these email addresses are never accidentally re-added to an active marketing list and receive emails again. This is a common and effective way to manage opt-outs while respecting recipient preferences.
Balancing CAN-SPAM with data privacy laws
While CAN-SPAM is the primary U.S. law governing commercial email, it's crucial to remember that other data privacy regulations exist globally and domestically. Laws like the General Data Protection Regulation (GDPR) in Europe and various state-level privacy laws in the U.S. (e.g., CCPA/CPRA in California) have strict requirements regarding data retention and the right to erasure (the right to be forgotten). Long retention periods for unsubscribed contacts could potentially conflict with these laws if a user requests their data to be fully deleted. You should also consider legal timeframes for unsubscribing email addresses by country.
CAN-SPAM perspective
Unsubscribe processing: Requires honoring opt-out requests within 10 business days.
Mechanism upkeep: Unsubscribe mechanism must be active for at least 30 days after sending.
Data retention: No specific mandate to keep unsubscribed addresses for an extended period beyond fulfilling opt-out.
GDPR and other privacy laws
Right to erasure: Data subjects can request deletion of their personal data.
Data minimization: Encourages retaining data only as long as necessary for the stated purpose.
Conflict potential: Long-term retention of unsubscribed contacts could clash with these deletion rights, unless there is a clear legal basis for retention.
A robust data privacy policy should clearly state your organization's data retention practices, including how long you keep information on unsubscribed or opted-out individuals. Transparency is key to maintaining trust and avoiding legal issues.
Best practices for managing unsubscribed contacts
While CAN-SPAM doesn't dictate a four-year retention, effective management of unsubscribed addresses is vital for your email program's health and to prevent being placed on an email blocklist (or blacklist). Here are some best practices:
Use a suppression list: Instead of outright deleting unsubscribed addresses, move them to a suppression list. This prevents them from ever being re-added to your active mailing lists, even if imported from another source, without explicit re-opt-in. This aligns with the principle that opt-out requests do not expire.
Process promptly: Aim to process unsubscribe requests immediately, not just within the 10-business-day legal window. Delaying can lead to recipient frustration, spam complaints, and potentially impact your sender reputation.
Distinguish email types: CAN-SPAM primarily applies to commercial emails. Transactional emails (e.g., order confirmations, shipping updates, security alerts) are generally exempt from unsubscribe requirements, although it's still good practice to allow preferences where appropriate. Make sure you understand whether a transactional email requires an unsubscribe link.
Maintaining a clean email list by promptly honoring unsubscribe requests is not only a legal obligation but also a crucial aspect of good email deliverability. Sending to unengaged or opted-out contacts can lead to increased spam complaints, lower inbox placement rates, and potential listing on email blocklists.
Views from the trenches
Best practices
Always use a robust suppression list for unsubscribed contacts to prevent accidental re-mailing, ensuring compliance and good sender reputation.
Process unsubscribe requests as quickly as possible, ideally in real-time, even though CAN-SPAM allows up to 10 business days.
Regularly review your data retention policies to align with all applicable privacy laws like GDPR, not just CAN-SPAM.
Common pitfalls
Misinterpreting CAN-SPAM's requirements or conflating them with general legal record-keeping statutes.
Delaying unsubscribe processing beyond 10 business days, which can lead to legal penalties and higher spam complaints.
Failing to maintain an active suppression list, risking re-mailing opted-out contacts and damaging deliverability.
Expert tips
Use the List-Unsubscribe header to support one-click unsubscribe, which is increasingly mandated by major mailbox providers.
Segment your audience carefully and tailor email content to reduce unsubscribe rates in the first place.
Regularly audit your email list for inactive or unengaged subscribers and consider a re-engagement campaign before suppression.
Marketer view
Marketer from Email Geeks says they have been in the email space for almost 20 years and have never heard of a four-year retention claim for unsubscribes under CAN-SPAM.
2022-05-27 - Email Geeks
Expert view
Expert from Email Geeks says that a four-year retention period for unsubscribed email addresses is not a CAN-SPAM requirement and might even conflict with data deletion requests under other privacy regulations.
2022-05-27 - Email Geeks
Key takeaways for unsubscribe compliance
The assertion that CAN-SPAM requires holding unsubscribed email addresses for four years is a misconception. The Act mandates timely processing of opt-out requests within 10 business days and maintaining the unsubscribe mechanism for 30 days, but it does not specify a longer retention period for the addresses themselves.
While businesses might choose to retain unsubscribe records for internal legal or auditing purposes, this is a company policy, not a federal requirement under CAN-SPAM. In fact, prolonged retention could conflict with other data privacy laws that grant individuals the right to have their data deleted. Prioritizing prompt unsubscribe processing and maintaining a robust suppression list remains the most effective and compliant approach for email marketers.
