The card with the tiny metallic square became more common after Oct. 1, which was when liability for covering fraudulent transactions shifted to the party that hadn't adopted chip technology - either the merchant or the credit-card issuer.
For merchants, that meant ensuring their sales terminals had a slot to read the new cards, as well as the software to accept these payments. The American Bankers Association estimates that 70 percent of credit cards will be chip-enabled by the end of the year.
"I think what's happening is just people are getting used to this change," said Matt Schulz, senior analyst at CreditCards.com. "You have customers that are confused, you have people behind the counter that are confused, and you have a process that takes a little bit longer.
"You add all that up, and it leaves you with a little bit longer lines at retailers."
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