Certificate of Authority

A Certificate of Authority is the license issued by the New York State Department of Taxation and Finance that allows a business to collect sales tax. Home improvement contractors in NYC must have one if they perform any taxable services—such as repairs, maintenance, installation, or other non–capital improvement work.

You cannot legally charge, collect, or remit sales tax without a Certificate of Authority.

In short: if you bill customers for any taxable home improvement work, you need a Certificate of Authority before you start charging sales tax.