What payment method is prohibited for purchasing money orders?

Purchasing money orders using a credit card is prohibited primarily due to the risk of fraud and the potential for money laundering associated with this payment method. Credit cards allow for the easy accumulation of debt and can be used for transactions that may not reflect the user's actual cash flow. This raises concerns for financial institutions about the legitimacy of the purchases being made, as money orders can be converted to cash or transferred without leaving a trace, which can facilitate illegal activities.

In contrast, cash, debit cards, and electronic transfers are generally accepted for purchasing money orders, as they provide more direct transactions that can be tracked and monitored. These methods align more closely with the regulations governing the sale of money orders, which aim to ensure that transactions are secure and legitimate.