Form 15658 – SB/SE Secure Messaging Business Taxpayer Agreement

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It looks like a California form to some readers, and it is not. Form 15658 is the IRS SB/SE Secure Messaging Business Taxpayer Agreement and Authorization of Disclosure to Designated Users (Rev. June 2025, Catalog Number 95538R), which a business with an EIN signs to exchange documents tied to one specific compliance activity through Secure Messaging.

The trap is treating it as standalone access. Each User you list in Appendix A still needs an accepted Form 2848 or Form 8821 on file before access begins, and Appendix A tops out at five Users. The agreement only takes effect once the IRS accepts it, and it ends the moment that compliance activity closes.

Key Takeaways

• Form 15658 is the IRS SB/SE Secure Messaging Business Taxpayer Agreement (Rev. June 2025, Catalog Number 95538R) that a business taxpayer with an EIN signs to exchange compliance-activity documents with the IRS through Secure Messaging. Each User listed on Appendix A also needs an accepted Form 2848 (POA) or Form 8821 (TIA) on file before access begins.
• It is scoped to one specific compliance activity and tax period. Secure Messaging may be used only to send and retrieve documents related to that activity, not as a general IRS inbox or account access.
• The agreement carries 12 numbered terms. Among them, the taxpayer must keep monitoring mail, phone, and fax, the U.S. government does not guarantee the security of data sent electronically, and the taxpayer pays its own and its Users' costs.
• Appendix A lists a maximum of 5 Users, each in one of three categories: Other Authorized Individual, POA (Form 2848), or TIA (Form 8821). Exactly one category box is required per User, and the signer must also appear in Appendix A.
• The agreement takes effect only when the taxpayer signs it and the IRS accepts it, and it is nullified when the compliance activity is completed, ending access to the messages and documents exchanged.

What “Form 15658” Actually Covers

Form 15658 sets up two things. First, it records the business taxpayer and the tax period for one specific IRS compliance activity. Second, it lists the Users the taxpayer wants to authorize for Secure Messaging in Appendix A. Beyond those two functions, the agreement carries 12 numbered terms the taxpayer agrees to, and Secure Messaging may be used only to send and retrieve documents related to that one compliance activity. It takes effect only once the taxpayer signs it and the IRS accepts it, and it is nullified when the compliance activity is completed. If you keep those guardrails in mind, you will complete the correct form and send it to the right place.

Quick mental model, “Form 15658 is the IRS agreement that opens Secure Messaging, and each User’s Form 2848 or Form 8821 is what actually unlocks their access.”

The Required Fields At A Glance

The form itself is short. Here is what you fill in, working top to bottom:

• The taxpayer name and the tax period ending date in the agreement opening, naming the one compliance activity it covers.
• The 12 numbered terms the taxpayer agrees to (no fields to complete, but read them with the client).
• The name of the taxpayer and the name and title of the individual signing, who must also be listed in Appendix A.
• The signature and date on the signature line.
• Appendix A: the taxpayer name, Employer Identification Number, and up to 5 Users with one category box checked each, plus each User's email and telephone.

Who Counts As A User

Appendix A recognizes three User categories, and exactly one box must be checked per row:

• Other Authorized Individual for someone with legal authority to bind the entity without a POA or TIA, generally a corporate officer, partner, tax matters partner, or partnership representative.
• POA for a User who has provided an accepted Form 2848 and is eligible to practice before the IRS.
• TIA for a User who has provided an accepted Form 8821, which grants information access only, not representation.

How To Complete And Submit Form 15658

I advise teams to treat this as a short, repeatable routine so nothing stalls while an exam clock runs.

1. Confirm you have the right form for the right party.

• Verify the taxpayer is a business with an EIN; Form 15658 is the SB/SE business form and Appendix A requires an EIN.
• Confirm the IRS examiner has opened a compliance activity, because the agreement is scoped to that one activity and tax period.

2. Fill in the agreement opening and read the terms.

• Enter the taxpayer name and the tax period ending date.
• Walk the client through all 12 numbered terms, especially the cost and no-security-guarantee provisions.

3. Complete Appendix A carefully.

• List no more than 5 Users, each with name, email, and telephone, and confirm every entry is legible.
• Check exactly one category box per User: Other Authorized Individual, POA, or TIA.
• Make sure the individual signing the agreement is also listed in Appendix A.

4. Line up each User's separate authorization.

• Match every POA box to an accepted Form 2848 and every TIA box to an accepted Form 8821 covering the right tax type and periods.
• Return the signed agreement to the IRS through the channel the examiner specifies. Access begins only after the IRS accepts it.

When Access Begins And Ends

Stage	What Triggers It	Practical Effect
Effective	Taxpayer signs and the IRS accepts the agreement	Secure Messaging opens for the named compliance activity; signature alone is not enough
User access	An accepted Form 2848 or Form 8821 is on file for that User	The listed User can log in, limited to the tax type and periods on the authorization
Nullified	The compliance activity is completed	The taxpayer and Users lose access to the messages and documents exchanged

Use of Secure Messaging is voluntary and optional, conveys no rights, and may be terminated at any time. The taxpayer can also stop using it by properly notifying the IRS that it no longer wishes to communicate electronically.

Authorizing Users: Form 2848 vs Form 8821

This is where most access problems start. Listing a User on Appendix A is not the same as authorizing them. Item 4 of the agreement requires that, in addition to Form 15658, an executed Form 2848 or Form 8821 be received and accepted by the IRS for the relevant tax type and periods before that User can access Secure Messaging. The two forms are not interchangeable.

Form 2848, Power of Attorney and Declaration of Representative, authorizes an individual to represent the taxpayer before the IRS, and that individual must be eligible to practice before the IRS. Form 8821, Tax Information Authorization, authorizes any individual, corporation, firm, organization, or partnership the taxpayer designates to inspect and receive confidential information, but it grants no representation rights. So check the POA box only for Form 2848 holders, and the TIA box only for Form 8821 designees.

What The 12 Numbered Terms Commit You To

The body of Form 15658 is a list of 12 terms the taxpayer agrees to. They are worth reading in full with the client, but here are the ones that surprise people most often:

• Documents will be exchanged through Secure Messaging rather than mail or fax, but Secure Messaging carries only some, not all, IRS communications, so the taxpayer must keep monitoring mail, phone, and fax.
• The IRS may expand the compliance activity to additional tax periods, and this same agreement automatically covers those periods.
• Each User must be separately authorized, and a User's access is limited by the Form 2848 or Form 8821 on file.
• The agreement is effective only when signed and accepted, remains in effect for the duration of the activity, and is nullified when the activity is completed.
• Use is voluntary and conveys no rights; nothing waives the sovereign immunity of the United States.
• The U.S. government does not guarantee the security of data sent electronically, and the taxpayer pays its own and its Users' costs, including internet, data, identity-theft protection, and credit monitoring.

A Simple Workflow To Stay Clean

• Tag every engagement to the one compliance activity and tax period named on the agreement.
• Keep a running map of each Appendix A User to their accepted Form 2848 or Form 8821 and the periods it covers.
• Re-check that map every time the IRS adds tax periods, since the agreement rolls forward but the User authorizations do not.

Appendix A Field Checklist For Your Team

Print this and keep it next to the agreement when you build Appendix A.

• Taxpayer name and Employer Identification Number at the top of Appendix A.
• Each User's full name, exactly as it should read for the IRS.
• Exactly one category box per User: Other Authorized Individual, POA, or TIA.
• Each User's email address and telephone number.
• No more than 5 Users total.
• The individual who signs the agreement appears as one of the listed Users.
• For every POA box, an accepted Form 2848 on file; for every TIA box, an accepted Form 8821 on file, both matching the tax type and periods.
• Every entry legible, since the form asks specifically for legible text.

POA vs TIA, Quick Compare

Field	POA, Form 2848	TIA, Form 8821
What it grants	Authority to represent the taxpayer before the IRS	Authority to inspect and receive confidential information only
Who can be named	An individual eligible to practice before the IRS	Any individual, corporation, firm, organization, or partnership
Appendix A box	Check the POA box	Check the TIA box
Access scope	Limited to the tax type and periods on the accepted form	Limited to the tax type and periods on the accepted form

Common Mistakes That Slow Down Case Triage

Most of the trouble I see with Form 15658 comes from treating it like a master key to the taxpayer's IRS account. It is not. It opens one narrow channel for one compliance activity, and these are where teams trip.

Expanded Periods And Ending Access

Two events during the activity catch teams off guard. First, the IRS may expand the compliance activity to additional tax periods. The Form 15658 agreement rolls forward to cover them automatically, but a User's access does not. If the added periods are not on that User's Form 2848 or Form 8821, the IRS must receive and accept a new or updated authorization before the User can see the new-period documents. Build that re-check into your routine every time periods are added.

Revoking A User And Closing Out

If the taxpayer revokes a User's authority on Form 2848 or Form 8821, that User loses access to the taxpayer's information. Revocation has to follow IRS procedures; simply asking the User to stop logging in does not revoke access. When the compliance activity is completed, the agreement is nullified and everyone loses access to the messages and documents exchanged, so download and save anything you need before the activity closes.

When you are handling sensitive taxpayer data, confirm scope and authorization every time. A short check beats discovering a gap mid-exam.

Real World Tips From The Operations Side

• Pre build a packet. Keep a current Form 15658, a one page Appendix A checklist, and a User-to-authorization map in a shared secure folder.
• Confirm acceptance, not just signing. Track the date the IRS accepts the agreement, because that is when access can begin, not the signature date.
• Train for handoffs. If your point person is out, the next teammate should be able to update Appendix A and the matching 2848 or 8821 without guessing.
• Log everything. Save the accepted agreement and each User's authorization in the case file so scope is easy to audit.
• Do a two minute scope check. Ask, does every Appendix A box match an accepted form covering the right tax type and periods, and is the signer listed.

How we work matters as much as what we send. The right party, the right boxes, the right authorizations, every time.

One Page Reference, Who Goes In Which Column

The User is	Appendix A box	Authorization on file	Keep in mind
A corporate officer, partner, tax matters partner, or partnership representative	Other Authorized Individual	None required for the box itself; they bind the entity by legal authority	Use only for individuals who can bind the entity
A representative authorized to act before the IRS	POA	Accepted Form 2848	Must be eligible to practice before the IRS
A designee allowed to receive information only	TIA	Accepted Form 8821	No representation rights; may be an individual or an entity

Appendix A holds a maximum of 5 Users, exactly one box per User, and the signer of the agreement must be one of them.

A Short Word On Process Discipline

You already run a busy operation, maybe a finance team, a tax practice, or a compliance function inside a larger organization. Managing an exam is detailed and time sensitive, so a little structure pays off. Keep SOPs for the agreement and Appendix A, standardize filenames, and use version control so reviewers can follow the trail. That way, when the agreement and authorizations leave your desk, they read clean, complete, and easy to audit.

If you work with outside partners, expect the same discipline. At Accountably, we obsess over documentation clarity, file naming, and review checklists for regulated work, because they cut review time and prevent rework. The same habits keep Secure Messaging enrollment moving. Mentioning this here is not about selling you anything, it is about building a repeatable process that keeps your team steady under an exam clock.

Final Checklist Before You Submit

• Taxpayer confirmed as a business with an EIN.
• Taxpayer name and tax period ending date entered; the one compliance activity is named.
• All 12 terms read with the client, including cost and no-security-guarantee provisions.
• Appendix A lists no more than 5 Users, each with exactly one category box.
• Every POA box matches an accepted Form 2848, every TIA box an accepted Form 8821.
• The signer appears in Appendix A.
• All names, emails, and telephone numbers legible.
• You will track the IRS acceptance date, since access begins only after acceptance.

You keep an exam moving when the agreement and authorizations are clean and complete. The form gives you the structure. Your process turns it into action.

Sources And Freshness

This guide reflects federal IRS guidance for Form 15658 reviewed on October 30, 2025. We relied on IRS Form 15658, the SB/SE Secure Messaging Business Taxpayer Agreement (Rev. June 2025, Catalog Number 95538R), and the IRS Secure Messaging Terms of Service and Rules of Conduct published at www.irs.gov/connect. We also referenced the IRS guidance on Form 2848, Power of Attorney and Declaration of Representative, and Form 8821, Tax Information Authorization, for the User-authorization requirements. Always confirm details against the current IRS instructions for your facts.

Reusable Checklists

These are copy-paste ready for your firm SOPs. Each item maps to a line on Form 15658 or its Appendix A, so a reviewer can work straight down the list.

Keep 15658 Season From Stalling

When a client lands in an SB/SE compliance activity, the pressure is to stand up secure document exchange fast. Form 15658 sets up the entity-level agreement, but per the form (June 2025) it is only the start: it carries 12 numbered terms, caps the User list at 5, and leaves each representative's access dependent on a separate Form 2848 or Form 8821 already accepted by the IRS.

The fix is to treat Form 15658 enrollment as a short, repeatable workflow rather than a one-time signature, so nothing stalls while an exam clock runs.

• Confirm the signer also appears in Appendix A with the correct category box before routing the agreement for signature.
• Tie every Appendix A User to an accepted Form 2848 or Form 8821 that matches the exact tax type and periods under exam.
• Re-check User authorizations each time the IRS expands the activity to new periods, since the agreement rolls forward but the 2848 or 8821 scope does not.
• Keep the client's mail and phone monitoring running, because Secure Messaging does not replace statutory notices.
• Archive every exchanged document before the activity closes, since access ends when the agreement is nullified.

This is the kind of structured, checklist-driven execution we build for clients through Accountably's tax services, so compliance activities move without missed authorizations or last-minute scrambles.

FAQs

What is IRS Form 15658

Form 15658 is the IRS SB/SE Secure Messaging Business Taxpayer Agreement and Authorization of Disclosure to Designated Users (Rev. June 2025, Catalog Number 95538R). A business taxpayer with an EIN signs it to exchange documents tied to a specific IRS compliance activity through Secure Messaging, and may list up to 5 Users in Appendix A.

Does signing Form 15658 give a User access to Secure Messaging

Not by itself. Listing a person in Appendix A only tells the IRS who the taxpayer wants to authorize. Each User also needs an executed Form 2848 (Power of Attorney) or Form 8821 (Tax Information Authorization) that the IRS has received and accepted for the right tax type and periods before that User can access Secure Messaging.

Can Form 15658 be used by an individual taxpayer

No. Form 15658 is the SB/SE business form. Appendix A requires an Employer Identification Number, so it is intended for business taxpayers under an IRS compliance activity, not individual filers.

Does Secure Messaging replace mail, phone, and fax with the IRS

No. Item 3 of the agreement states Secure Messaging is limited to some, but not all, IRS communications. The taxpayer must keep monitoring mail, phone, and fax to meet its legal obligations, because statutory notices can still arrive through those channels.

How many Users can I list on Appendix A

Appendix A allows a maximum of 5 Users and provides five rows. Each row needs exactly one category box checked: Other Authorized Individual, POA, or TIA. The individual who signs the agreement must also be listed in Appendix A.

What happens to Secure Messaging when the compliance activity ends

Item 8 nullifies the agreement when the compliance activity is completed. The taxpayer and its Users then lose access to view the messages and documents exchanged during it, so download and save anything important before the activity closes.