A blacklisted IMEI is one that has been added to the GSMA Device Registry (the global blacklist database) after being reported lost, stolen, or unpaid by a carrier. A blacklisted phone is blocked from connecting to most carrier networks worldwide, regardless of which SIM is inserted.
Blacklisting happens for three primary reasons:
- Reported stolen / lost, the original owner or insurer reports the device.
- Unpaid carrier contract, the device was purchased on instalment or contract and the customer stopped paying. The carrier then blacklists the IMEI even though the physical device may be perfectly functional.
- Insurance fraud flag, the carrier or insurer suspects fraudulent claims.
The GSMA blacklist is independent of Apple's iCloud Activation Lock system, a phone can be iCloud-clean but blacklisted, or vice versa. Both must be checked separately during wholesale verification.
Major IMEI blacklist check services include CheckMEND, IMEI24, and individual carrier check pages. A blacklisted phone trades at parts value, a small fraction of the clean-device price, because it cannot be reused as a working device on most networks. Some markets (parts of Latin America, Africa, Eastern Europe) have networks that don't check the GSMA blacklist, creating a small grey-market export channel.