A fixed amount of taxes assessed equally on all taxpaying entities regardless of their income level. Lump-sum taxes, such as sales taxes, property taxes on cars and business equipment, and excise taxes, are thought to be regressive since lower income people must apply a higher percentage of their income to the tax. In theory, a lump sum income tax system could be more efficient because it wouldn't be predicated on the ability to pay or a person's willingness to work.