How to Fill Out and Use the ST-4 Certificate of Exemption

Massachusetts does not issue a form called ST-3. Searchers looking for the Massachusetts ST-3 certificate of exemption almost always want Form ST-4, the Sales Tax Resale Certificate, which lets a registered business buy tangible personal property or taxable services without paying the state’s 6.25% sales tax when the purchase is for resale in the regular course of business.¹ If your exemption is for a different reason, Massachusetts uses Form ST-5 for tax-exempt organizations and Form ST-12 for manufacturers claiming exempt use of materials, tools, and fuel.² What follows walks through the ST-4: who can use it, how to fill it out, and how to keep out of trouble.

Who Can Issue an ST-4

Two conditions have to be met. First, the purchaser must hold a valid Massachusetts vendor registration.¹ Registration is done through MassTaxConnect at mass.gov/dor, and the Department of Revenue mails a certificate of registration (Form ST-1) for each location, which must be posted visibly.³

Second, you actually have to be buying the item to resell it. Under M.G.L. c. 64H, § 8, every sale a vendor makes is presumed to be a taxable retail sale unless a resale certificate is collected from the buyer.⁴ A retail clothing store can use an ST-4 to stock its shelves. That same store cannot use one to buy an office printer, cleaning supplies, or break-room furniture, because those items are consumed by the business rather than resold. The 6.25% tax applies to those purchases.⁵

If you issue a certificate and later put the property to any use other than holding it for sale, demonstration, or display, sales or use tax applies as of the moment you first put it to that other use.¹ Buying something “just in case” you might resell it is not enough. You need real resale intent, or a genuine inability at the time of purchase to determine whether the item will be resold or consumed.⁶

How to Fill Out Form ST-4

Download Form ST-4 from the Massachusetts Department of Revenue website at mass.gov. The form fits on one page and has fields for both the purchaser and the vendor.

Purchaser’s name, exactly as it appears on your Massachusetts registration.
Your Account ID number or federal Employer Identification Number. Either one works.¹
Full business address.
Type of business, described briefly (for example, “retail electronics” or “wholesale food distribution”).
Type of property or service being purchased, described as specifically as possible. “Various goods” is the kind of vagueness that draws audit attention.
Vendor’s name and full address.
Certificate type: single purchase or blanket.
Signature, title, and date. The vendor is required to confirm the certificate is filled out properly and signed before accepting it.¹

The property description is where most mistakes happen. If a hardware store writes “building materials” but the invoice shows a commercial coffee machine, that mismatch is exactly what auditors look for. Match the description to what your business actually sells.

Single Purchase or Blanket Certificate

A single purchase certificate covers one transaction. A blanket certificate stays on file with the vendor and covers all qualifying purchases of the same general category going forward, so you don’t fill out a new form each time.¹

Blanket certificates save time with regular suppliers, but they carry a risk. Because the certificate stays open-ended, every purchase from that vendor in the covered category is presumed to be for resale. Slip in an order for something the business will use internally, and the blanket certificate doesn’t protect that transaction. You’ll owe the tax plus interest. Review blanket certificates periodically to make sure they still describe what you actually resell.

Giving the Certificate to the Vendor

Hand the completed ST-4 to your vendor at or before the time of purchase so the tax isn’t added to the invoice. Paper or electronic delivery both work, depending on what the vendor accepts. The key is that the vendor has it before completing the sale as tax-exempt.

If the vendor never receives a certificate and the Department of Revenue later asks for proof the sale was exempt, the vendor has 60 days from the date of the Commissioner’s notice to produce a valid certificate. Miss that window, and the vendor has to prove through other evidence that the sale wasn’t a taxable retail transaction.⁴ That is a much harder position, which is why vendors insist on the certificate upfront.

What Vendors Should Check Before Accepting One

Massachusetts places the burden of proving a sale is non-taxable on the vendor, and the resale certificate is the primary way to shift that burden.⁶ Accepting a certificate in good faith shields the vendor from liability for the uncollected tax, but good faith has limits.

Good faith is questioned when the vendor knows facts suggesting the buyer doesn’t actually intend to resell the goods. The classic example from the form instructions: a purchaser buying merchandise that has nothing to do with the type of business they claim to operate.¹ A landscaping company presenting a resale certificate for a flat-screen television should prompt questions. Accepting that certificate without pushback can cost the vendor the good-faith protection.

Before accepting a certificate, confirm every field is completed and the form is signed. Vendors can also verify a buyer’s registration status through MassTaxConnect.⁵

Out-of-State Buyers and Tobacco

Two boundaries are worth flagging because they trip up buyers who assume the standard rule applies.

Massachusetts is not a member of the Streamlined Sales Tax Agreement.⁷ The multistate Streamlined Exemption Certificate does not automatically work here. An out-of-state buyer without Massachusetts nexus who wants to make a tax-exempt purchase from a Massachusetts vendor cannot use a standard ST-4. Instead, the vendor can accept a signed statement on the buyer’s letterhead, or with a business card attached, declaring under pains and penalties of perjury that the purchase is for resale.⁵ A buyer that does have Massachusetts nexus needs to register and use the ST-4.

Resale certificates are also flatly invalid for tobacco products. Massachusetts bars use of an ST-4 for tobacco regardless of resale intent.⁵ Tobacco wholesalers and retailers operate under separate tax rules.

How Long to Keep the Certificate

Both parties need to keep their copy. The form instructions tell vendors to retain the certificate as part of their permanent tax records.¹ Purchasers are covered by 830 CMR 62C.25.1, which requires every holder of a resale certificate to keep a record of each purchase made under it.⁸

At a minimum, hold on to it until the statute of limitations for additional tax assessments runs out. The general assessment period is three years after the return was filed or was due, whichever is later. It stretches to six years if the Department of Revenue determines a taxpayer omitted more than 25% of gross income or tax from a return, and there is no time limit at all for fraudulent returns or failure to file.⁹ The safe practice is at least six years, and indefinitely if any filing was incomplete.

Penalties for Misuse

Using a resale certificate to avoid tax on items you don’t intend to resell is not just a paperwork problem. The ST-4 form carries a printed warning: willful misuse can result in criminal tax evasion sanctions of up to one year in prison and fines of up to $10,000 for individuals or $50,000 for corporations.¹

The statutory basis is M.G.L. c. 62C, § 73, which makes it a criminal offense to willfully present a certificate known to be fraudulent or false in order to evade sales or use tax. The same section reaches anyone who helps prepare or present a false certificate, so an accountant or bookkeeper who fills out resale certificates knowing the purchases aren’t for resale shares the risk.¹⁰ Beyond criminal exposure, the Department of Revenue will assess unpaid tax and interest back to the date of the original purchase, and misuse discovered in an audit that reveals omissions above 25% of reported tax expands the assessment window from three years to six.⁹

Common Mistakes to Avoid

Most ST-4 problems are not fraud. They’re sloppiness. A few patterns come up again and again:

Vague property descriptions like “merchandise” or “supplies.” Auditors compare the certificate against the invoices, and generic wording invites scrutiny.
Missing or lapsed registration. The certificate requires a valid Massachusetts vendor registration. A wrong Account ID or an expired registration makes the certificate invalid from the start.
Using the wrong form. Manufacturers claiming an exemption for raw materials, tools, or fuel used in production should use Form ST-12. Tax-exempt nonprofits making purchases for their own use need Form ST-5. An ST-4 will not cover an exemption that belongs to another category.
Unsigned certificates. Vendors are required to confirm the form is signed before accepting it, and an unsigned ST-4 protects neither party.
Mixing personal and business purchases. The Department of Revenue reconciles federal income tax returns against sales tax filings, and inconsistencies between reported sales and claimed exemptions draw attention fast.

When the Commissioner finds a deficient certificate, the vendor gets 60 days to correct it. If the vendor can’t fix it in time, the burden shifts back to proving through other means that the sale was not taxable.¹¹

1
Massachusetts Department of Revenue. Form ST-4 Sales Tax Resale Certificate
2
Massachusetts Department of Revenue. Form ST-5 Sales Tax Exempt Purchaser Certificate
3
Massachusetts Department of Revenue. Register Your Business with MassTaxConnect
4
General Court of Massachusetts. Massachusetts Code Chapter 64H – Section 8
5
Massachusetts Department of Revenue. Sales and Use Tax
6
Massachusetts Department of Revenue. Massachusetts Code 830 CMR 64H.8.1 – Resale and Exempt Use Certificates
7
Streamlined Sales Tax. Massachusetts
8
Massachusetts Department of Revenue. 830 CMR 62C.25.1 – Record Retention
9
Massachusetts Department of Revenue. 830 CMR 62C.26.1 – Assessments
10
General Court of Massachusetts. Massachusetts Code Chapter 62C – Section 73
11
Massachusetts Department of Revenue. 830 CMR 64H.8.1 – Resale and Exempt Use Certificates