“Section 145(3)”

Foreign exchange fluctuations, whether gains or losses, are inextricably linked to the underlying business transaction and must be accounted for under the mercantile system. The Supreme Court also affirmed the standard accounting principle of valuing stock at cost or net realisable value, whichever is lower.

The Assessing Officer loses jurisdiction and the entire reassessment becomes invalid if no addition is made in respect of the income that formed the basis of the reopening. Explanation 3 to Section 147 does not permit assessing other escaped income unless an addition is made for the original income forming the reason to believe.

Tax liability for an item of income or expenditure is determined solely by the provisions of the Income-tax Act. Entries in an assessee's books of account are not conclusive and do not govern the taxability or deductibility of an item, as the legal rights and obligations under the Act prevail.

Where an assessee maintains regular books of account, and these books are not rejected or found defective by the Assessing Officer, any cash deposits or available cash shown in the cash book, if sufficient to cover the transaction, cannot be treated as unexplained income or an addition under sections 68 or 69A.

When books of account are rejected and unaccounted sales or receipts are discovered, the income addition is restricted to the net profit element embedded in these undisclosed transactions, not the entire sale proceeds or receipts, especially if corresponding purchases are not proven to be outside the books.

Where purchases are found to be non-genuine or fictitious, a reasonable disallowance of 25% of such purchases or the peak credit, whichever is higher, can be made. This is applied to address unexplained expenditure under Section 69C when actual goods are likely procured from the grey market.

Transactions defying human probability cannot be applied to isolated purchases if sales are accepted as genuine, and purchases cannot be disallowed without considering the entire transaction and documentary evidence. Failure to produce parties in an assessment proceeding may not be fatal to the assessee.

In a best judgment assessment, some guesswork is inherent, but the estimate must be fair and not arbitrary. Books of account can be rejected under Section 145(3) if the assessee fails to substantiate entries or prove the genuineness of transactions, leading to estimation of income.