NEW YORK (CNNMoney) -- Declined! Your debit card may soon be denied for purchases greater than $100 -- or even as little as $50. JPMorgan Chase, one of the nation's largest banks, is considering capping debit card transactions at either $50 or $100, according to a source with knowledge of the proposal. Why? Because of a tricky thing called interchange fees. Right now, every time you swipe your debit card, your bank charges the retailer an average fee of 44 cents, which it shares with its partners. Those little fees, however, add up to about $16 billion per year, according to 2009 data from the Federal Reserve. But as part of the Wall Street reform legislation that was passed last year, these fees are being slashed. The Fed is currently proposing rules that would go into effect in July and would cap interchange fees at 12 cents.