Rebate for securities transaction tax allows deduction against income-tax attributable to business securities transactions when proof of payment is filed. Section 88E grants a rebate equal to securities transaction tax paid in respect of taxable securities transactions forming part of business income, deductible against the income-tax attributable to that income, limited to the amount of such income-tax and conditional upon furnishing prescribed evidence of payment; the income-tax attributable to such income is determined by applying the average rate of income-tax, and statutory definitions of taxable securities transaction and securities transaction tax apply.