Deductions from interest on securities: proportional allocation of expenses and borrowed-interest for banking companies, with legislative omission noted. Section 20 provided proportional allocation rules for banking companies whereby expenses admissible under sections 30, 31, 36 and 37 and interest on moneys borrowed were apportioned in the same proportion as gross receipts from taxable interest on securities bore to the company's total gross receipts in the profit and loss account; the apportioned amounts were not again deductible under those sections, and 'moneys borrowed' included deposits.