An Activity License is required for all businesses and non-profits operating in Philadelphia. Instructions for registering a business in Philadelphia, including how to choose your business structure and get a City tax account number.Learn about forming and registering your business online, and how to complete other types of business filings. Register your business (opens in a new tab). A Commercial Activity License ("CAL") allows you to own and run a business in Philadelphia including renting out units for residential housing. Searchable online database of homes for sale, rent, and not currently on the market, with value estimator, market report, and real-estate trend tool. The Philadelphia Sheriff's Office uses Bid4Assets as a platform to provide auction services. This webpage covers information important to understanding property taxes in Philadelphia. You can find a list of real estate tax assistance programs here. Property in the City of Philadelphia between 1865 and 1955.