New York Resale Certificate vs. Certificate of Authority: What Each Document Does

The Certificate of Authority and Form ST-120 Resale Certificate serve different purposes. A New York Certificate of Authority establishes that a business is registered with the New York State Department of Taxation and Finance for sales tax purposes. It authorizes the business to collect sales tax and to issue or accept most New York sales tax exemption certificates. Form ST-120, by contrast, is the transaction document a qualifying purchaser gives to a seller when buying property or services for resale or transfer to customers.

For many New York resellers, the documents work together: the business first obtains a valid Certificate of Authority and then uses its registration information when issuing Form ST-120 for eligible purchases. The resale certificate is not a replacement for sales tax registration, and obtaining a Certificate of Authority does not automatically make every business purchase tax-exempt.

How the two documents differ

The easiest way to distinguish the documents is to ask what each one proves.

• Certificate of Authority: Proves that the business is registered as a New York sales tax vendor. It authorizes the business to collect sales tax and issue or accept most New York sales tax exemption certificates.
• Form ST-120 Resale Certificate: Documents the purchaser’s claim that a particular qualifying purchase—or a category of qualifying purchases under a blanket certificate—is for resale or transfer to customers.

The Certificate of Authority concerns the business’s sales tax registration status. Form ST-120 concerns the tax treatment of purchases made for resale. A retailer may therefore need both documents but use them at different stages of its operations.

For example, a retailer buying qualifying inventory for resale may issue Form ST-120 to its supplier. When that retailer later sells taxable merchandise to a customer, its Certificate of Authority permits it to collect the applicable sales tax as a registered vendor. Form ST-120 does not authorize the retailer to collect sales tax from customers; that authority comes from its registration.

Businesses that want more detail about the transaction document can review New York Form ST-120 Resale Certificate: How to Complete It. Businesses evaluating the registration side can read How to Get a New York Sales Tax Certificate of Authority for Online Sellers.

Who needs a Certificate of Authority

Every person selling taxable tangible personal property or taxable services in New York must register with the Tax Department. This rule includes home-based sellers, temporary vendors, and businesses that make sales only once a year.

A business required to register must apply for its Certificate of Authority at least 20 days before it begins operations or purchases the assets of another business. For the online application method, the business registers through New York Business Express and needs a NY.gov Business account.

Registration should be considered separately from whether the business expects to buy inventory for resale. A seller may have a registration obligation because of what it sells, while its ability to use Form ST-120 depends on what it is buying and whether that purchase satisfies the resale conditions.

After receiving a Certificate of Authority, a business can check the identifying information and registration status before relying on it for exemption-certificate transactions. See How to Verify a New York Certificate of Authority for a focused explanation.

Who may use Form ST-120

A purchaser registered as a New York sales tax vendor may use Form ST-120 when it has a valid Certificate of Authority and buys qualifying property or services for resale or transfer to customers. Motor fuel and diesel motor fuel are excluded from the form’s permitted uses.

The resale purpose is central. A Certificate of Authority does not turn ordinary business expenses, equipment used by the business, or other nonresale purchases into resale transactions. The purchaser should evaluate the intended disposition of the property or service rather than treating Form ST-120 as a general purchasing credential.

Specified purchasers that are not required to register in New York may also use Form ST-120, but only when they satisfy all applicable conditions on the form concerning out-of-state registration, location, delivery, and resale. This is a conditional route, not a broad exception for any company headquartered outside New York. A business with a New York registration obligation cannot rely on the out-of-state provisions merely because it lacks physical presence in the state.

Contractors cannot use Form ST-120. The form directs contractors to applicable alternatives such as Form ST-120.1, Contractor Exempt Purchase Certificate, or Form AU-297, Direct Payment Permit, or instructs them to pay sales tax. A contractor should not describe a construction-related purchase as resale and issue ST-120 simply because materials will become part of a customer’s project.

How registration and resale documentation work

1. Determine whether sales tax vendor registration is required. Consider whether the business will sell taxable tangible personal property or taxable services in New York. If registration is required, address the Certificate of Authority before beginning taxable sales.
2. Apply within the required window. A required applicant must submit its Certificate of Authority application at least 20 days before beginning operations or purchasing another business’s assets. The online method uses New York Business Express and requires a NY.gov Business account.
3. Separate resale purchases from business-use purchases. Before issuing Form ST-120, identify whether the property or service will actually be resold or transferred to customers under the form’s conditions. Registration by itself is not the basis for exempting an unrelated purchase.
4. Prepare the appropriate certificate. A New York purchaser using ST-120 should have a valid Certificate of Authority and provide the requested purchaser, seller, registration, purchase, and resale information accurately. For a more detailed preparation overview, see How to Get a Resale Certificate in New York: What to Prepare.
5. Choose single-use or blanket treatment where permitted. Form ST-120 may be marked as a blanket certificate for purchases of the same general type. If it is not marked as blanket, it is treated as a single-use certificate. Temporary vendors may not issue blanket resale certificates.
6. Give the completed ST-120 to the seller. The purchaser does not submit the certificate to the Tax Department. The seller retains it as documentation for the transaction. To receive timely-certificate treatment, the seller must possess a properly completed certificate within 90 days of the transaction; this applies to paper and electronic exemption certificates.

After registration or delivery of Form ST-120

The parties have different responsibilities after the documents are issued. The purchaser should use Form ST-120 only for purchases that meet its eligibility and resale requirements. If a blanket certificate is used, it covers purchases of the same general type rather than every purchase from that seller without regard to purpose.

The seller should keep the completed resale certificate rather than forwarding it to the Tax Department. A seller receiving a certificate should make sure it is properly completed and connected to the relevant transaction or qualifying blanket purchases. The 90-day possession rule makes prompt delivery important even though the purchaser, not the seller, prepares the certificate.

The Certificate of Authority remains the registration document behind a New York vendor’s sales tax activities. If a business later ends the activities covered by its registration, cancellation is a separate process from simply stopping the use of resale certificates. Businesses in that position can consult How to Cancel a New York Certificate of Authority.

Practical examples

Retail inventory purchase

A New York-registered shop purchases qualifying merchandise that it plans to resell to retail customers. The shop’s Certificate of Authority establishes its sales tax vendor registration. It gives its supplier a properly completed Form ST-120 to document the qualifying resale purchase. The supplier keeps the certificate; it does not file the form with the Tax Department.

Purchase for the business’s own use

The same shop purchases items it will use in its operations rather than resell or transfer to customers. Its possession of a Certificate of Authority does not, by itself, make those items eligible for Form ST-120. The intended use of the purchase does not satisfy the resale purpose described by the form.

Recurring purchases from one supplier

A non-temporary vendor repeatedly buys the same general type of qualifying resale merchandise from a supplier. It may mark Form ST-120 as a blanket certificate rather than issuing a separate certificate for every covered purchase. The blanket designation does not extend to purchases outside the qualifying general type or to items bought for the purchaser’s own use.

Temporary vendor

A temporary vendor making taxable sales must register even if its selling activity is brief. It may not issue a blanket resale certificate. If it otherwise qualifies to use Form ST-120, its certificate is limited to single-use treatment.