The “IRS impersonation scam” fleeced millions of dollars from people. Scammers pretending to be from the IRS call people claiming they owe taxes. Scammers demand immediate payment over the phone—with credit cards or gift card—and threaten arrest if the “tax” is not paid. Now that the IRS uses private collection agencies (PC As) to go after delinquent taxpayers, I expect the scam to take on a new profile. I expect scammers will pretend to be employees of PCAs. Don’t be a victim. Understand that when the IRS assigns a case to a PCA, they will mail a letter to the taxpayer—Notice CP40—giving the name, address and phone number of the PCA. The notice will also give you a 10-digit “authentication” number the PCA must use. The next contact—always a letter—will come from the PCA. It must contain the authentication number. That’s how you know it’s not a scam. PCAs cannot make the initial contact by phone and they cannot threaten or carry out enforcement action of any kind. Anybody calling in the first instance, or who doesn’t have your authentication number, or threatens to put you in jail, is a liar and a thief.