IRS Form 15658 Guide: SB/SE Secure Messaging for Audits

Introduction: What Is IRS Form 15658?

IRS Form 15658, officially titled SB/SE Secure Messaging Business Taxpayer Agreement and Authorization of Disclosure to Designated Users, is an administrative digital consent document issued by the Internal Revenue Service (IRS). Governed by the Department of the Treasury, this form is administered through the Small Business/Self-Employed (SB/SE) division of the IRS.

When a small business, partnership, corporation, or self-employed individual is selected for an IRS examination, exchanging financial records, accounting ledgers, and audit responses through traditional postal mail can be slow and inefficient. To modernize this process, the IRS created the Taxpayer Digital Communications Secure Messaging for Businesses (TDC SM-B) system.

Form 15658 serves as the formal legal agreement that allows business taxpayers under audit to participate in secure digital messaging. By completing this form, an authorized business officer consents to electronic communications and officially designates specific employees or representatives who are permitted to access the portal and exchange confidential audit records directly with the IRS.

Purpose of the Form: Why Does Form 15658 Exist?

Under Internal Revenue Code (IRC) Section 6103, federal tax returns and return information are strictly confidential. The IRS is legally prohibited from transmitting sensitive tax data electronically or discussing audit details with company personnel unless the business provides explicit, written disclosure authorization.

Historically, businesses under audit had to mail paper binders, send faxes, or coordinate in-person agent visits. This created delays, increased administrative costs, and left businesses waiting weeks for written responses to simple questions.

Form 15658 solves these operational challenges by creating a secure legal bridge to digital audit management. It establishes clear security protocols, outlines platform terms of use, and identifies authorized individuals within the company who can send and receive digital files. This enables businesses to respond to Information Document Requests (IDRs) quickly, eliminate paper postage costs, and accelerate the completion of their tax examination.

Who Needs to File Form 15658?

Form 15658 is designed for business entities undergoing an active examination conducted by the IRS Small Business/Self-Employed division:

• Businesses Under SB/SE Audit: C corporations, S corporations, partnerships, limited liability companies (LLCs), and sole proprietors that want to communicate with their revenue agent electronically.
• Companies with Multiple Accounting Staff: Businesses that want to authorize internal team members—such as a Chief Financial Officer, corporate controller, or in-house tax manager—to upload records and receive audit updates.
• Businesses Updating Authorized Portal Users: Existing participants in the TDC SM-B program who need to add new staff members or revoke access for former employees during an ongoing examination.

Who Is Exempt or Not Required to File?

Because Form 15658 is an optional digital communication tool, several groups have no obligation to complete it:

• Businesses Choosing Paper or In-Person Audits: Participation in secure messaging is entirely voluntary. If a business prefers to correspond by certified postal mail, fax, or in-person meetings, Form 15658 is not required.
• Taxpayers Under Non-SB/SE Audits: Entities audited by the Large Business & International (LB&I) division or Tax Exempt & Government Entities (TE/GE) division use separate divisional procedures (such as Form 15314 for TE/GE).
• Individual Non-Business Filers: Wage earners undergoing routine correspondence audits through the Wage & Investment division use individual online accounts and do not file Form 15658.
• Businesses Not Under Audit: Companies filing routine annual tax returns (such as Form 1120 or Form 1065) have no need for this form.

When to File: Deadlines and Frequency

Form 15658 is an event-based administrative form with no annual calendar deadline:

• Audit Inception: Businesses typically complete Form 15658 at the beginning of an examination after the revenue agent or tax compliance officer introduces the digital communication option.
• Mid-Audit Staff Adjustments: The form can be resubmitted at any time during an open examination to add new designated users or remove individuals who have changed roles or left the company.
• Duration of Effectiveness: Once accepted, the authorization remains in effect for the duration of the specific audit or until formally revoked in writing by the business.

Where and How to File Form 15658

Form 15658 is handled directly between the business taxpayer and the assigned IRS audit team:

Direct Submission to Examining Agent: The completed and signed form is transmitted directly to the assigned IRS revenue agent or auditor handling your case. This can be done via secure email, secure fax, or during an initial audit conference.

Mail Delivery: If physical mailing is required, send the executed document to the specific examiner at the official IRS address as per instructions provided on your formal audit appointment letter.

Step-by-Step Instructions to Fill Out Form 15658

Form 15658 requires clear identification of the business entity, acceptance of digital terms, and detailed disclosures for every individual granted access to the secure messaging portal.

Section / Part	Field Description	Required Information & Operational Objective
Part 1	Business Taxpayer Identification	Enter legal business name, Employer Identification Number (EIN), physical address, phone, and primary contact.
Part 2	Terms of Service & Consent	Acknowledge and agree to the digital platform rules, security responsibilities, and electronic disclosure terms.
Part 3	Designated Users Roster	List the full legal names, corporate titles, direct individual business email addresses, and phone numbers of authorized internal users.
Part 4	Representative Coordination	Identify whether outside CPAs or attorneys are involved, confirming that an active Form 2848 is on file.
Part 5	Signature & Legal Authority	An authorized individual with legal authority to bind the entity signs and dates under penalties of perjury.

Detailed Walkthrough of Form Requirements

Step 1: Enter Business Details (Part 1). Provide your exact legal business name, Employer Identification Number (EIN), and current physical business address. Ensure these entries match your filed federal tax returns and the IRS examination notice.

Step 2: Review and Accept Electronic Terms (Part 2). Carefully review the digital communications consent terms. Under these terms, the business agrees that notifications of new IRS messages will arrive via automated emails containing no personal tax data, prompting authorized users to log into the secure portal to view messages.

Step 3: List Designated Internal Users (Part 3). Enter the names, job titles, and direct business email addresses of the specific employees you are authorizing. Do not use shared group email accounts (such as info@company.com or accounting@company.com); each designated user must have an individual, direct email address for identity verification.

Step 4: Coordinate with Outside Representatives (Part 4). If your company is represented by an external CPA, enrolled agent, or tax attorney, confirm that Form 2848 (Power of Attorney) is already on file. Form 15658 authorizes internal company personnel to use the messaging portal; it does not replace the formal legal representation powers granted under Form 2848.

Step 5: Sign with Legal Binding Authority (Part 5). The form must be executed by an individual who possesses legal authority to bind the business entity. For a corporation, this is typically a corporate officer (President, Vice President, Treasurer); for a partnership, a general partner; for an LLC, a managing member; and for a sole proprietorship, the owner.

Required Documents and Information Needed Before Filling

Before completing Form 15658, gather the following records and case information:

• IRS Examination Notice: Keep your initial audit notice handy to reference your case number, tax periods under examination, and the assigned revenue agent’s name.
• Corporate Identification Details: Exact legal entity name, registered business address, and federal EIN.
• Designated User Information: Full legal names, official job titles, and individual business email addresses for all staff members who will participate.
• Form 2848 (Power of Attorney): A copy of your executed representation forms if external accountants or legal counsel will participate in messaging threads.
• Proof of Corporate Authority: Corporate bylaws, operating agreements, or partnership documents confirming the signatory’s legal power to bind the organization.

Common Mistakes to Avoid

Errors on Form 15658 can delay your access to the secure messaging portal. Watch out for these frequent mistakes:

• Using Generic or Shared Email Addresses: Listing shared inboxes (such as taxes@business.com) violates federal security protocols. The IRS requires unique, individual email addresses for every user.
• Unauthorized Signatures: Having a bookkeeper, administrative assistant, or non-officer sign the form invalidates the submission. The form must be signed by an individual with legal authority to bind the entity.
• Confusing Designated Users with Legal Representatives: Authorizing an employee on Form 15658 allows them to exchange messages and upload files, but it does not authorize them to represent the business in legal tax controversies like an attorney or CPA under Form 2848.
• Failing to Revoke Access for Departing Staff: If an authorized user leaves the company, the business must immediately notify the revenue agent in writing to terminate that individual’s portal access.
• Submitting the Form Outside an Active Audit: Attempting to file Form 15658 when your business is not under an active SB/SE examination will result in rejection, as the messaging portal is open only to active audit cases.

Consequences of Non-Filing or Communication Breakdowns

Because Form 15658 is an optional authorization agreement, there are no penalties or fines for choosing not to file it. However, failing to manage audit communications effectively carries serious risks:

• Reliance on Slow Postal Mail: Without secure digital messaging, all audit questionnaires, document requests, and workpapers must move through the postal system, extending the audit by weeks or months.
• Missed Information Document Request (IDR) Deadlines: Postal delays can cause your business to miss strict response deadlines, prompting the examiner to make unfavorable audit adjustments.
• Issuance of a Statutory Notice of Deficiency: If communication breaks down and audit deadlines pass without substantiation, the IRS will close the audit as “unagreed” and assess additional taxes, compounding interest, and mandatory 20% Accuracy-Related Penalties under IRC Section 6662.

Related Forms and Publications

Form 15658 works alongside several key IRS audit and authorization documents:

• Publication 6057: Taxpayer Digital Communication – Secure Messaging for Businesses (TDC SM-B overview).
• Form 2848: Power of Attorney and Declaration of Representative.
• Form 8821: Tax Information Authorization.
• Form 15314: TE/GE Secure Messaging Taxpayer Agreement Authorization of Disclosure to Designated Users (the counterpart for tax-exempt entities).
• Form 1120 / Form 1120-S: Corporate and S Corporation Income Tax Returns.
• Form 1065: U.S. Return of Partnership Income.
• Publication 583: Starting a Business and Keeping Records.

Frequently Asked Questions (FAQs)

Is using IRS secure messaging mandatory during a business audit?

No. Using the TDC SM-B platform is completely voluntary. Businesses that prefer traditional postal mail, telephone calls, or face-to-face meetings can continue to use those methods without penalty.

Can external accountants or attorneys be listed on Form 15658?

External advisors who hold an active Form 2848 (Power of Attorney) on file with the IRS can participate in secure messaging. However, Form 15658 is primarily used to authorize internal company employees who do not have formal power of attorney.

What happens when the IRS sends a secure message to my business?

When an examiner posts a message or uploads a document to your portal, authorized users receive an automated email notification. To protect taxpayer privacy, the email contains no tax data or identifying information; users must log into the secure portal to read the message.

Can a business authorize more than one employee on Form 15658?

Yes. The form allows the business to designate multiple users, such as a CFO, controller, and accounting manager, ensuring that audit requests can be handled smoothly even if one employee is out of the office.

What file types can be uploaded through the secure messaging system?

The TDC SM-B platform supports common business file formats, including PDF, Microsoft Word, Excel spreadsheets, and image files (JPEG, PNG). The system enforces file size limitations per transmission as detailed in user instructions.

How can a business revoke a user’s access on Form 15658?

To revoke access, an authorized corporate officer must submit a written notification or an amended Form 15658 directly to the examining agent, specifying the name and email address of the individual whose access should be terminated.

Conclusion: Key Takeaways

IRS Form 15658, SB/SE Secure Messaging Business Taxpayer Agreement and Authorization of Disclosure to Designated Users, provides a modern, efficient way for small businesses and self-employed taxpayers to manage federal tax audits. By replacing slow postal correspondence with encrypted digital messaging, businesses can resolve audit questions quickly and securely.

To take advantage of this service, ensure that an officer with legal authority signs the agreement, provide individual business email addresses for all designated staff, and keep outside legal representatives properly authorized through Form 2848. Using Form 15658 streamlines communication, reduces administrative burdens, and helps bring your tax audit to a fast, well-documented resolution.