Collection of tax at source by e commerce operators; non-matching supplier returns can increase supplier output tax liability. Electronic commerce operators must collect tax at source at the time of credit or payment, remit collected amounts to the appropriate Government within ten days after month-end, and file an electronic monthly statement detailing amounts collected for each supplier. Collected amounts are deemed tax payments on behalf of suppliers, who claim credit in their electronic cash ledger. Operator-submitted details are matched with suppliers' returns; discrepancies notified to both parties, unrectified discrepancies are added to the supplier's output tax liability and attract interest. Authorities may require operators to furnish supply or stock details; non-compliance may incur a penalty.