Sturdy payment card mainstay American Express's (AXP -3.42%) stock was looking a bit rickety on the last trading day of the week. The company's shares lost more than 3% of their value on Friday following a report in a top financial newspaper regarding the potential defection of an important customer base. By comparison, the S&P 500 index only fell by slightly over 1% that day.

Potential instability in stability

That morning, The Wall Street Journal published an article stating that some of the largest American retailers are considering how to use stablecoins in their businesses. Stablecoins are cryptocurrencies that are pegged to a fiat currency, such as the dollar, and typically buttressed by cash or relatively liquid securities.

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Citing unidentified "people familiar with the matter," the newspaper wrote that influential companies in the sector, such as Walmart and Amazon, are even considering whether to issue their own stablecoins. The Journal also flagged sprawling online travel agency Expedia Group as a business exploring such an option.

The attraction of payment instruments like stablecoins is that, if implemented well, they could save retailers vast amounts of money in fees. A key source of revenue for card payment companies is the small charges they impose on merchants accepting their cards, hence the negative AmEx investor reaction to the news.

A Genius idea

How far such efforts go will depend on the fate of the Genius Act, a proposed law making its way through Congress that would erect a regulatory framework for stablecoins. If it successfully makes it through the legislative process and becomes law in some useful form, stablecoins could indeed become a money-saving instrument convenient for U.S. retailers and their customers.