It seems there is more than one number - I received a call today from 877-572-0188. I was not available so they left a message. When I called it and an automated system asked for my debit card number, I hung up and investigated. I called the number on the back of my card and talked to a telephone banker who transferred me to the "debit card fraud prevention" office. Before transferring, she gave me their direct number as 800-978-8664
. That office confirmed that they DID call my home to ask about a number of recent transactions. She ran through the transactions and all were legit (although a couple were big and out of the ordinary for me). So, the bottom line is that it was a legitimate call from Chase, although I agree with the general advice not to give out your info unless YOU have initiated the call to a verified legitimate number.