Many Reddit users report receiving $10.xx checks for money owed to them as being American Express Business cardholders. Apparently there were $10 wireless credits not paid out and these are being sent out with interest. Some people got $20.xx check or $30.xx checking, presumably for some months combined. Some got even a dozen or more of these checks. It’s been sent even to people who are not aware of any missing credits, so keep an eye out and don’t throw out the mail too quickly.
Source: doctorofcredit.com