Taxpayers should use these forms and guides to apply for local tax abatements and exemptions and file property returns. Pay Personal Property Taxes Online enables online payments for personal property tax bills received from Middlesex County.A single personal property assessment is made for all taxable personal property of the owner located in the city or town. 2. The New Business Tangible Personal Property Form is intended for first-time filers only. Sales tax applies to retail sales of certain tangible personal property and services. The Treasurer is the chief financial officer for Middlesex County, collecting taxes and local fees, and making payments on behalf of the local government. Request for Extension to file Business Tangible Personal Property Tax Return. Property Tax Reimbursement Forms (PTR) May Be Filled Out on the Following Days and Times. Business Tangible Personal Property Return Form, reporting all furniture, fixtures, tools and equipment used in a trade or business.