The selling of items or services generates money for many businesses. As a result, revenue is sometimes referred to as gross sales. Other kinds of income are also available. Licensing, patents, and royalties are all possible sources of income for inventors and performers. Rental income may be a source of income for real estate investors. Tax revenues from property or income taxes would most likely be the source of revenue for the federal and local governments. Governments may also profit from the sale of an asset or from interest income from a bona fide bond. Donations and grants are the most common sources of funding for charities and non-profit organizations. Universities might profit not just from tuition fees, but also from investment earnings on their endowment funds.