Investment allowance for qualifying plant and equipment reduces taxable business income subject to reserve and utilisation conditions. Investment allowance grants a deduction on acquisition or installation of specified new ships, aircraft, machinery or plant used wholly for business, subject to exclusions for office/residential installations, office appliances, road transport vehicles and assets qualifying for other full deductions. The allowance is limited by taxable total income with any unallowed balance carried forward for up to eight assessment years. A required portion must be credited to an Investment Allowance Reserve Account and utilised within ten years to acquire qualifying new assets for the business; misuse or premature disposal renders the allowance wrongly made.