Even small ones. Fraudsters often test stolen card information with tiny charges — $0.99, $1.00, $2.47 — before making larger withdrawals. A single unrecognized charge is worth investigating immediately. Do not assume it is a billing error until you have confirmed what it is.

A collection agency calling about a debt you know nothing about is one of the clearest signals that someone has opened an account in your name. Do not ignore these calls or assume they are mistakes. Request written verification and immediately check your credit report.

If your card is declined when you know there is available balance or credit, call your card issuer immediately. It may mean your account has been compromised, funds have been drained, or a fraud alert has been placed on your account by the bank after detecting suspicious activity.

If bank statements, credit card bills, or other financial correspondence suddenly stops arriving, someone may have filed a change of address in your name to redirect your mail. This is often an early step in financial identity theft, done to buy time before you notice fraudulent activity.

This is the most definitive sign of identity theft. Check your credit report at AnnualCreditReport.com and look for every account listed. Any account you do not recognize — credit card, loan, retail account, utility — was opened by someone else using your information.

A sudden unexplained drop in your credit score — especially if you have not missed payments or applied for new credit — may indicate that fraudulent accounts are being opened or that existing accounts are being maxed out in your name.

Each time someone applies for credit in your name, the lender runs a hard inquiry on your credit report. Multiple hard inquiries from banks, auto dealers, or credit card companies you have never interacted with means someone is actively trying to open accounts using your identity.

Being turned down for a loan, credit card, or apartment rental when you believe your credit is in good standing is a serious signal. The lender sees something on your credit report that you have not looked at recently — check it immediately.

This is tax identity theft — someone filed a return using your Social Security number and claimed your refund. File IRS Form 14039 (Identity Theft Affidavit) immediately, then file your legitimate return on paper. See our complete guide to what to do if someone filed your taxes.

Check your Social Security earnings record at SSA.gov/myaccount. If you see wages from employers you do not recognize, someone is using your SSN to work — which can affect your future Social Security benefits and create tax complications.

Fraudulent unemployment claims, Medicaid applications, or other government benefit applications filed using your SSN are a form of identity theft that surged during the pandemic and continues at elevated levels. You may find out via a letter from the relevant agency.

Receiving unsolicited password reset requests, two-factor authentication codes, or account verification emails for accounts you didn’t initiate means someone is trying to access your accounts. Change the password for that account immediately and check whether any access was gained.

A sudden loss of phone service — where calls and texts stop working completely — may be a SIM swap attack. A criminal convinced your carrier to transfer your number to a SIM they control, giving them access to all SMS-based two-factor authentication codes. Contact your carrier immediately.

Medical identity theft occurs when someone uses your health insurance to receive care. You may receive Explanation of Benefits statements from your insurer for procedures or visits that never happened, or bills from medical providers you have never seen.

If your insurer denies a legitimate claim saying you have exhausted your annual benefit limit — when you know you have not used it — someone else may have been receiving care under your policy. Contact your insurer’s fraud department immediately.