USPS Ancillary Endorsements Explained (2025): Forwarding, Returns & Address Corrections
Complete guide to USPS ancillary service endorsements including Return Service Requested, Address Service Requested, Do Not Forward, and Change Service Requested. Learn how each endorsement affects mail forwarding, returns, and fees.
What are USPS ancillary service endorsements?
USPS ancillary service endorsements are special markings printed on mail that tell the Postal Service how to handle undeliverable-as-addressed (UAA) mail. These endorsements control whether mail is forwarded, returned, or discarded, and whether the sender receives address correction information. The four main endorsements are Return Service Requested, Address Service Requested, Change Service Requested, and Forwarding Service Requested. A fifth option, Do Not Forward, prevents forwarding entirely. Each endorsement has different effects on First-Class Mail versus other mail classes, and may trigger fees for returns or address corrections.
Complete USPS Ancillary Endorsements Reference Table
The table below shows all USPS ancillary service endorsements, how they affect mail handling, and what fees apply. Understanding these endorsements is critical for businesses managing mailing lists and ensuring important documents reach their intended recipients.
| Endorsement | If Undeliverable | If Forwarding Order Exists | Address Correction? | Fees (First-Class) | Fees (Other Classes) |
|---|---|---|---|---|---|
| Return Service Requested | Returned to sender with reason | Returned to sender with new address | Yes (separate notice) | Free return + free address | Return postage + address fee |
| Forwarding Service Requested | Returned to sender with reason | Forwarded to new address | Yes (separate notice) | Free return + free address | Return postage + address fee |
| Address Service Requested | Returned to sender with reason | Forwarded + sender gets new address | Yes (separate notice) | Free forward + free address | Forward postage + address fee |
| Change Service Requested | Mail discarded (not returned) | Forwarded + sender gets new address | Yes (separate notice) | Free forward + free address | Forward postage + address fee |
| Do Not Forward | Returned to sender | Returned to sender (not forwarded) | No | Free return | Return postage |
| No Endorsement | Handled per mail class rules | Forwarded if eligible | No | Free forward | Varies by class |
Important: First-Class Mail and First-Class Package Service receive free forwarding and free return service regardless of endorsement. Other mail classes (Marketing Mail, Periodicals, Package Services) may incur forwarding or return postage charges plus address correction fees.
How Each Endorsement Works: Detailed Explanations
Return Service Requested
Return Service Requested is one of the most commonly used USPS endorsements. It instructs the Postal Service to return undeliverable mail to the sender rather than forwarding it, even if the recipient has filed a change of address.
How it works:
- If the recipient has moved and filed a forwarding order, USPS returns the mail to you with the new address printed on a label
- If the address is invalid or the recipient is unknown, USPS returns the mail with the reason marked
- You also receive a separate address correction notice (Form 3547) with the new or corrected address information
- For First-Class Mail, return service and address corrections are free
Best for: Businesses that need to verify recipient addresses, maintain clean mailing lists, or ensure time-sensitive documents don't sit in forwarding limbo. Common for financial statements, tax documents, legal notices, and subscription renewals.
Forwarding Service Requested
Forwarding Service Requested allows mail to be forwarded if a forwarding order exists, but requests that USPS inform the sender of the new address so the mailing list can be updated.
How it works:
- If the recipient has a forwarding order, USPS forwards the mail and sends you a separate address correction notice with the new address
- If the mail is undeliverable and no forwarding order exists, it's returned to sender
- You receive address correction information either way, helping you update your records
Best for: Businesses that want mail to reach the customer while also maintaining updated mailing lists. Balances customer service (mail reaches them) with data hygiene (you get the new address).
Address Service Requested
Address Service Requested is similar to Forwarding Service Requested but provides more flexibility depending on the mail class and how long the forwarding order has been active.
How it works:
- For First-Class Mail with an active forwarding order, the mail is forwarded and you receive the new address
- For other mail classes (Marketing Mail, etc.), the mailpiece may be returned with the new address rather than forwarded, depending on forwarding time limits
- You always receive address correction information via separate notice (Form 3547)
- If undeliverable with no forwarding order, mail is returned
Best for: High-volume mailers who prioritize address accuracy and want to avoid sending mail to outdated addresses long-term. Commonly used for catalogs, promotional mail, and periodicals.
Change Service Requested
Change Service Requested prioritizes address data over mail delivery. It provides the sender with updated address information but does not return undeliverable mail.
How it works:
- If a forwarding order exists, the mail is forwarded and you receive the new address
- If the mail is undeliverable with no forwarding order, it is discarded rather than returned to sender
- You receive a separate address correction notice (Form 3547) in both scenarios
- This endorsement saves return postage costs but means undeliverable mail is thrown away
Best for: High-volume bulk mailers sending low-value items (catalogs, flyers, promotional mail) where list hygiene is more important than guaranteed delivery of each individual piece. Not recommended for important documents or account statements.
Do Not Forward
Do Not Forward prevents USPS from forwarding mail even if the recipient has an active change of address order. The mail is returned to sender instead.
How it works:
- If the recipient has moved and filed a forwarding order, the mail is not forwarded—it's returned to sender
- If the address is invalid, the mail is returned with the reason marked
- No address correction information is provided
- For First-Class Mail, return postage is free; for other classes, return postage applies
Best for: Legal notices, court documents, or compliance mail where you need to verify the recipient still resides at the address on file. Also used for address verification purposes.
Warning: "Do Not Forward" is risky for customer-critical mail like credit card statements, renewal notices, or account alerts. If your customer has moved and filed a forwarding order, they won't receive the mail—it will come back to you instead. Use this endorsement carefully and only when address verification is more important than mail delivery.
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Send Mail Online →When Businesses Must Use Ancillary Endorsements
USPS does not require ancillary endorsements on most mail, but certain situations and mail types strongly benefit from—or in some cases mandate—their use:
Automation Rate Mail (CASS Certification)
Mailers using USPS automation rates must maintain address accuracy and use Move Update processes. Ancillary endorsements like Address Service Requested or Return Service Requested help fulfill this requirement by identifying moved recipients.
Financial and Legal Mail
Banks, credit unions, tax services, and legal senders often use Return Service Requested or Do Not Forward to ensure statements, tax documents, and legal notices reach the intended address of record. Forwarding these documents could create compliance or security risks.
Subscription and Membership Renewals
Magazines, membership organizations, and subscription services often use Address Service Requested to keep mailing lists current while still delivering issues to forwarding addresses during the transition period.
Marketing Mail with High Return Costs
Bulk mailers sending catalogs or promotional packages may use Change Service Requested to update addresses without paying return postage on every undeliverable piece, since the mail is discarded rather than returned.
How Endorsements Affect Undeliverable-as-Addressed (UAA) Mail
When mail cannot be delivered as addressed, USPS marks it as Undeliverable-as-Addressed (UAA). What happens next depends entirely on the ancillary endorsement (or lack thereof):
| Mail Class | No Endorsement | With Endorsement |
|---|---|---|
| First-Class Mail | Returned to sender free; forwarded free if COA exists | Returned or forwarded per endorsement; sender receives address correction notice |
| Marketing Mail | Discarded (not returned); no address correction provided | Returned, forwarded, or discarded per endorsement; sender receives address correction notice (with fees) |
| Periodicals | Discarded after limited forwarding period | Returned or forwarded per endorsement; address correction provided (with fees) |
| Package Services | Returned only if return postage guaranteed | Returned per endorsement; return postage charged |
Without an endorsement, Marketing Mail and Periodicals are typically discarded when undeliverable, and you receive no notification. This means you'll continue mailing to bad addresses unless you proactively use ancillary endorsements to request address corrections.
Best Practices for Using Ancillary Endorsements
1. Match the Endorsement to Your Mail's Purpose
Use Return Service Requested for financial statements, legal mail, and time-sensitive documents. Use Address Service Requested for catalogs and marketing mail where you want to maintain list accuracy. Use Change Service Requested for high-volume promotional mail where return costs outweigh individual piece value.
2. Print the Endorsement Clearly on Every Mailpiece
Ancillary endorsements must be printed clearly below the return address or above the delivery address. Use all caps (e.g., "ADDRESS SERVICE REQUESTED") to ensure visibility. The endorsement must appear on every piece—it cannot be printed only on outer envelopes of bulk trays.
3. Budget for Address Correction Fees
For mail classes other than First-Class, address correction notices and return/forwarding services incur fees (typically around $0.60–$1.00+ per piece depending on the service). Factor these costs into your mailing budget, especially for high-volume campaigns.
4. Process Address Corrections Promptly
When you receive Form 3547 address correction notices, update your mailing list immediately. Continuing to mail to outdated addresses wastes money and damages sender reputation. Many CRM and mailing platforms can automate this update process.
5. Avoid "Do Not Forward" Unless Truly Necessary
"Do Not Forward" should only be used when address verification is the primary goal. For customer-facing mail (account statements, renewal notices, service alerts), this endorsement can prevent your mail from reaching customers who have moved, leading to frustrated customers and potential compliance issues.
6. Combine Endorsements with Move Update (NCOA) Services
For best results, use ancillary endorsements in combination with National Change of Address (NCOA) processing before you mail. NCOA updates addresses proactively, while endorsements catch changes that occurred after your NCOA check. This two-layer approach minimizes UAA mail.
How The Letter Pilot Handles Address Verification
When you send mail through The Letter Pilot, we automatically validate and standardize addresses using USPS CASS-certified address verification before your mail is printed and sent. This process:
- Confirms the address exists in the USPS database
- Standardizes formatting (abbreviations, ZIP+4, etc.) to USPS specifications
- Flags invalid or incomplete addresses before you pay for postage
- Reduces undeliverable mail and the need for ancillary endorsements
For certified mail online and registered mail online, address verification is especially critical because these services require valid delivery addresses for proof of mailing and delivery tracking.
By using The Letter Pilot, you reduce the need for Return Service Requested or Address Service Requested endorsements because bad addresses are caught before mailing—saving you return postage costs and improving delivery rates.
Frequently Asked Questions About USPS Ancillary Endorsements
What does Return Service Requested mean on mail?
Return Service Requested means that if the mail is undeliverable, USPS will return the entire mailpiece to the sender and provide the new address if a forwarding order exists. For First-Class Mail, this service is free. For other mail classes, return postage and address correction fees may apply. This endorsement prevents mail from being forwarded to the recipient's new address.
What is the difference between Address Service Requested and Change Service Requested?
Address Service Requested provides address correction notices to the sender but still forwards or returns the mail, while Change Service Requested only provides address correction notices without returning the mailpiece. With Address Service Requested, First-Class Mail is forwarded and you receive the new address; with Change Service Requested, mail is forwarded but not returned even if undeliverable. Both help maintain clean mailing lists but handle the physical mail differently.
Why would you use Do Not Forward on mail?
Do Not Forward is used when you need mail to reach only the current address and not be forwarded to a new location. This endorsement is common for time-sensitive documents, legal notices, or when verifying someone still lives at a specific address. However, it can be risky for important mail because if the recipient has moved, the mail will be returned to sender rather than reaching them at their new address.
Do I have to pay for address corrections on First-Class Mail?
No. Address correction services are free for First-Class Mail and First-Class Package Service when you use any ancillary endorsement. However, for Marketing Mail, Periodicals, and other mail classes, USPS charges an address correction fee (typically $0.60–$1.00+ per correction) in addition to any forwarding or return postage.
What happens if I don't use any ancillary endorsement?
Without an endorsement, USPS handles undeliverable mail according to the default rules for that mail class. First-Class Mail is returned free and forwarded free. Marketing Mail and Periodicals are typically discarded when undeliverable, and you receive no notification—meaning you'll continue mailing to bad addresses unless you proactively use endorsements or NCOA services.
Can I use multiple endorsements on the same mailpiece?
No. You can only use one ancillary service endorsement per mailpiece. Printing multiple endorsements creates conflicting instructions for USPS and may result in the mail being processed incorrectly. Choose the single endorsement that best matches your priority (forwarding, returning, or address correction).
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📚 Related Guides
Return to Sender Guide
Understanding Undeliverable-as-Addressed (UAA) mail and return processes
Read more →USPS Change of Address Guide
How mail forwarding works and how to file a change of address
Read more →USPS Lost Mail Guide
How to file a missing mail search and track down lost packages
Read more →The information in this guide is for educational purposes only. The Letter Pilot does not guarantee USPS delivery times, routing, or processing speed. All mail is handled solely by the United States Postal Service, and actual delivery times may vary.
Delivery timelines and tracking information are provided by USPS and are not controlled by The Letter Pilot.