A UK tax allowance by which payers of mortgage interest are allowed to claim part of all of this as a deduction in calculating their taxable income. The argument for such relief is that those with mortgage payments are worse off than other taxpayers with equal incomes but no mortgage. The argument against is that such tax relief costs the government money which could be better spent on improving housing for those too poor to afford to buy their homes.

• income effect
• income elasticity of demand
• income expansion path
• income from employment
• income from self-employment
• income inequality
• income method
• income per capita
• income redistribution
• incomes and prices policy
• incomes policy
• income support
• income tax
• income velocity of circulation
• incomplete information
• incomplete markets
• increase in the book value of stocks and work in progress
• increasing function
• increasing returns to scale
• incremental capital-output ratio
• incumbent firm
• indefinite integral
• independence, central bank
• independent risks
• independent taxation of spouses