New York Sales Tax: Certificate of Authority and Form ST-120 Duties

A New York sales tax Certificate of Authority is the registration every business must obtain from the New York State Department of Taxation and Finance before it can collect sales tax or make taxable sales in the state. You apply on Form DTF-17, and the application has to be filed at least 20 days before your first taxable sale.¹ Selling without one is both a civil violation and a misdemeanor, and the people behind the business can be held personally liable for any tax the business fails to remit.

Who Needs a Certificate

Anyone who will collect sales tax, sell tangible goods or taxable services in New York, or buy products for resale needs a Certificate of Authority. That includes retail stores, restaurants, service providers, hotel operators, and vendors at trade shows or flea markets.¹ If your activity produces a taxable transaction in the state, you register first and sell second.

Remote sellers with no physical presence in New York still need to register once they cross two thresholds during the preceding four sales tax quarters: more than $500,000 in gross receipts from sales delivered into the state, and more than 100 individual sales delivered into the state.² Both conditions must be met. The same thresholds apply to marketplace providers that facilitate sales for third-party sellers, so if you sell only through a marketplace that already collects and remits tax on your behalf, that marketplace carries the registration burden for those sales. Any direct sales you make yourself, through your own website or a physical location, still require your own Certificate of Authority.

How to Apply

The application is Form DTF-17. File it at least 20 days before you plan to start making taxable sales, because you cannot legally sell until the Tax Department processes the application and mails you the certificate.¹ You can submit it through the New York Business Express online portal or by mail.

To complete the form, you’ll need:

Your federal Employer Identification Number.
The legal business name exactly as filed with the New York Department of State.
A physical address for every location where you’ll make taxable sales.
The name, Social Security number or ITIN, and home address for every officer, director, partner, or LLC member who qualifies as a responsible person.

That last item deserves attention. New York treats sales tax as money the business holds in trust for the state, and everyone listed as a responsible person becomes personally liable for unpaid tax regardless of the corporate form of the business.³

Where to Display It

Once the certificate arrives, New York Tax Law Section 1134 requires you to display it prominently at each place of business.⁴ If you have multiple locations, each needs its own certificate posted where customers can see it. Vendors without a fixed location, such as those working from a cart or truck, must attach the certificate to their merchandising setup.⁵

Penalties for Operating Without One

Selling taxable goods or services without a valid Certificate of Authority carries two layers of consequence.

On the civil side, New York can impose a penalty of up to $500 for the first day of operation without the certificate, plus up to $200 for each additional day, capped at $10,000.⁶

Criminally, willfully selling taxable goods or services without a valid certificate is a misdemeanor under New York Tax Law Section 1817.⁷ A second offense within five years of a prior suspension or revocation carries a mandatory minimum $500 fine on top of any other penalty. If someone keeps operating after the Tax Department revokes a certificate, the state can go to court for an injunction shutting the business down.⁴

Using Form ST-120 as a Registered Vendor

Once you hold a Certificate of Authority, you can use Form ST-120, the Resale Certificate, to buy inventory tax-free when those goods will be resold to your customers.⁸ Filling it out requires your Certificate of Authority number, a description of your business, and the categories of property you’re buying for resale. The form must be signed by the owner, a partner, or an authorized representative to be valid.⁹

You can issue a single-purchase certificate for one transaction, or a blanket certificate covering all qualifying purchases from the same vendor going forward. A blanket certificate does not expire on a set date. Either can be given to the seller at the time of purchase or within 90 days afterward.⁹

If you’re on the receiving end of a Form ST-120, you must accept it in good faith, meaning you had no reason to believe the information was false or the purchase wasn’t actually for resale. A properly completed certificate accepted in good faith shields you from liability for the uncollected tax.⁹ Accept it when you know the buyer is really purchasing for personal use and you can be held liable yourself. New York offers a free online lookup at ny.gov to confirm a buyer’s Certificate of Authority number is valid.¹⁰ Both parties must keep copies for at least three years after the due date of the return, or the date the return was filed, whichever is later.⁸

Misusing the form is expensive. If you buy something tax-free and then keep it for personal use, you owe use tax and must report it on your next sales tax return.⁸ Deliberate misuse carries a civil penalty of 100% of the tax that should have been paid, a $50 penalty for each fraudulent exemption certificate issued, possible felony charges, and revocation of your Certificate of Authority.

Personal Liability of Responsible Persons

Because New York treats collected sales tax as trust fund money, the Tax Department does not stop at the business when tax goes unpaid. It pursues the individuals who had authority over the business’s finances.

Owners, officers, partners, and LLC members identified on Form DTF-17 can be classified as responsible persons even without day-to-day involvement in operations.³ Check-signing authority, the power to hire and fire, and involvement in daily management all count. The burden of proof falls on the individual to show they had no duty to collect and remit the tax.

A silent investor in an LLC who never touches the books can still face a personal assessment for unpaid sales tax, interest, and penalties. LLC members in New York are liable regardless of their level of involvement, though minority members with no operational role may qualify for partial relief under a Tax Department policy.

Filing Requirements After You’re Registered

The certificate is the entry ticket. What keeps you compliant is filing sales tax returns on schedule, even for periods when you owe nothing. New York assigns a filing frequency based on volume: annual filing (for businesses owing $3,000 or less during the annual filing period, due March 20 each year), quarterly filing (the default, due within 20 days after the end of each quarter), or part-quarterly monthly filing (required once taxable receipts hit $300,000 or more in a quarter, due within 20 days after the end of each month).

You must file for every period even if sales were zero.¹¹ Skipping a zero-dollar return triggers the same late-filing penalties as skipping one where you owed money, starting at 10% of the tax due for the first month with a $50 minimum, and climbing from there with interest running at 14.5% per year or the underpayment rate set by the Tax Commissioner, whichever is higher.¹² Willfully failing to pay tax you collected from customers carries a penalty equal to twice the unpaid tax, plus interest.¹³

Closing, Selling, or Restructuring the Business

When your business stops operating, you cannot simply put the certificate away and stop filing. You have to destroy your Certificate of Authority and continue filing returns through your final reporting period. The Tax Department inactivates your account after processing the last return.¹⁴

Selling the business or its assets adds steps. Give the buyer a copy of Form TP-153 (Notice to Prospective Purchasers of a Business or Business Assets) and collect any sales tax due on the sale of business assets. Changing form, such as converting a sole proprietorship into a corporation, is handled the same way: destroy the old certificate, file a final return, apply for a new Certificate of Authority at least 20 days before the new entity begins operations, and submit Form AU-196.10 at least 10 days before the change takes place.¹⁴

1
New York State Department of Taxation and Finance. How to Register for New York State Sales Tax
2
New York State Department of Taxation and Finance. Registration Requirement for Businesses With No Physical Presence in New York State
3
New York State Department of Taxation and Finance. Instructions for Form DTF-17 – Application to Register for a Sales Tax Certificate of Authority
4
New York State Senate. New York Tax Law 1134 – Registration
5
Legal Information Institute. New York Code 20 NYCRR 533.1 – Registration Requirement
6
Legal Information Institute. New York Code 20 NYCRR 540.6 – Penalty for Conducting a Business Without Possessing a Valid Certificate of Authority
7
New York State Senate. New York Tax Law 1817
8
New York State Department of Taxation and Finance. Form ST-120 – Resale Certificate
9
New York State Department of Taxation and Finance. Exemption Certificates for Sales Tax
10
New York State. Registered Sales Tax Vendor Lookup
11
New York State Department of Taxation and Finance. Filing Requirements for Sales and Use Tax Returns
12
New York State Senate. New York Tax Law 1145 – Penalties and Interest
13
New York State Department of Taxation and Finance. Sales and Use Tax Penalties
14
New York State Department of Taxation and Finance. Amending or Surrendering a Certificate of Authority