Bad or doubtful debts rule for public companies defines non-performing assets and loss assets for interest income treatment. Clause (b) of section 43D applies to every public company where interest income relates to specified categories of bad or doubtful debts. The rule covers doubtful assets, meaning debts that have remained non-performing assets for more than two years, and loss assets, meaning debts identified as uncollectible but not written off in the accounts. It also specifies the kinds of non-performing assets covered, including certain term loans, lease rentals, hire purchase instalments, bills purchased or discounted, and other short-term credit facilities, with an amount treated as past due if unpaid for thirty days beyond the due date.