Deemed income for undisclosed investments and unexplained expenditure, and non-cheque hundi transactions treated as taxable income. Section 69B treats excess investments or acquisitions over amounts recorded in the Block of Assets as deemed income when explanations are absent or unsatisfactory; Section 69C permits unexplained expenditure to be deemed income and disallows it as a deduction; Section 69D deems amounts borrowed on or repaid on a hundi otherwise than by account payee cheque to be income, excludes reassessment on repayment if already deemed, and counts interest as part of repayment.