A spokeswoman for American Express said the company’s sonic logo plays on marketing channels such as brand videos, but not at any credit-card terminals. PREVIEWPayments firms say sonic logos at cash registers can also communicate to customers that they are transacting with a trusted merchant, making the sounds akin to the stickers of credit-card logos that often appear in store windows. Visa’s spokeswoman said the company doesn’t share figures on how many businesses play its sonic logo due to the complexity of tracking rollouts. To that suggestion, Mastercard said the value of sonic logos for merchants “comes in through consumer trust and reassurance.” Visa declined to comment. But some retailers want no part of sonic logos.

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