How Property Tax is Calculated. You will need to find both your Business.License Account and your Business Tangible Property Account Numbers. A single personal property assessment is made for all taxable personal property of the owner located in the city or town. 2. Southwest Middlesex produces and distribute property bills twice in each year. What is considered individual personal property? If, among other things, a purchaser has any place of business or salespeople in New York State, or owns or leases tangible personal property in the State,. In the event that property being transported in the personal vehicle, while it is being operated for.