Net winnings calculation for online gaming: new formula governs withholding and reporting of tax on withdrawals. The rules insert rule 133 prescribing algebraic formulas to compute net winnings from online games for tax and withholding purposes: annual net winnings equal (aggregate withdrawals + closing balance) less (non taxable deposits + opening balance); first withdrawal net winnings equal withdrawal less (non taxable deposits + opening balance) with a floor at zero; subsequent withdrawals subtract earlier net winnings already taxed; end of year net winnings combine aggregate withdrawals and balances less deposits, opening balance and previously taxed winnings. Explanations define non taxable/taxable deposits, aggregate treatment across user accounts, in kind/direct payments deemed as taxable deposits and withdrawals, exclusion and recharacterisation rules for promotional credits, and intra intermediary transfer treatment.