Something else that Durbin did not address is what will happen to the interchange fee when a purchase is returned by a customer.

FORBES: Digesting The Impending Durbin-related Doom

The IRS considers deposits returned on termination of a purchase agreement.

FORBES: Contract Cancellations Trigger Taxes

Merchants issue a refund in an amount equaling the full purchase price when an item is returned, but the retailer may be taking a loss on such transactions because card processing fees are not refunded when transactions are reversed.

FORBES: Digesting The Impending Durbin-related Doom

The government used some of these funds to purchase equity in US banks and industrial corporations, much of which had been returned to the government by early 2011.

FORBES: United States