BCBS Prefix List M2A to M9Z
The BCBS Prefix List M2A to M9Z is a key resource for healthcare providers, billing specialists, and administrative staff who work with Blue Cross Blue Shield insurance claims. Each BCBS member ID begins with a unique three-letter prefix. Prefixes in the M2A to M9Z range typically indicate group health plans, PPO networks, and employer-sponsored insurance policies. These prefixes help identify the correct BCBS company and regional office responsible for processing claims.
Using the correct prefix is essential for smooth claim processing. For instance, a member ID starting with “M5Z” corresponds to a specific BCBS division or state plan. Submitting claims without verifying the prefix can lead to delays, denials, or claims being routed incorrectly. Billing and front-office teams must always confirm the prefix before submitting claims to avoid these problems.
These prefixes also play a crucial role during eligibility verification. Staff can enter the prefix into BCBS online portals or payer systems to check coverage status, copays, deductibles, and prior authorization requirements. Verifying benefits ahead of time reduces claim denials and improves patient satisfaction.
Blue Cross Blue Shield operates as a network of independent companies across various states and regions. Each prefix corresponds directly to one of these companies. The BCBS Prefix List M2A to M9Z provides a reliable way to match member IDs to the correct payer.
Maintaining an updated prefix list helps billing teams increase accuracy and efficiency. It reduces errors, supports faster reimbursements, and lowers administrative workload. Medical offices handling numerous BCBS claims benefit greatly from using this list. Proper use of prefixes leads to smoother revenue cycle management and better billing operations.
| BCBS Prefix List M2A to M9Z | State lookup | BCBS compnay |
|---|---|---|
| M2A | - | Unallocated/Not Assigned |
| M2B | - | Unallocated/Not Assigned |
| M2C | Illinois | Blue-Cross Blue-Shield of Illinois |
| M2D | Illinois | Blue-Cross Blue-Shield of Illinois |
| M2E | Texas | Blue-Cross Blue-Shield of Texas |
| M2F | Texas | Blue-Cross Blue-Shield of Texas |
| M2G | Texas | Blue-Cross Blue-Shield of Texas |
| M2H | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M2I | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| M2J | Illinois | Blue-Cross Blue-Shield of Illinois |
| M2K | Arizona | Blue-Cross Blue-Shield of Arizona |
| M2L | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| M2M | California | Anthem Blue-Cross |
| M2N | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M2O | - | Unallocated/Not Assigned |
| M2P | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M2Q | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M2R | Texas | Blue-Cross Blue-Shield of Texas |
| M2S | Illinois | Blue-Cross Blue-Shield of Illinois |
| M2T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M2U | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M2V | Arizona | Blue-Cross Blue-Shield of Arizona |
| M2W | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| M2X | Montana | Blue-Cross Blue-Shield of Montana |
| M2Y | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M2Z | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M3A | Kansas | Blue-Cross Blue-Shield of Kansas |
| M3B | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| M3C | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| M3D | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M3E | Illinois | Blue-Cross Blue-Shield of Illinois |
| M3F | Texas | Blue-Cross Blue-Shield of Texas |
| M3G | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| M3H | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| M3I | - | Unallocated/Not Assigned |
| M3J | New York | Empire Blue-Cross Blue-Shield of New York |
| M3K | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M3L | Michigan | Blue-Cross Blue-Shield of Michigan |
| M3M | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M3N | Maine | Anthem Blue-Cross Blue-Shield of Maine |
| M3O | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M3P | Arizona | Blue-Cross Blue-Shield of Arizona |
| M3Q | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| M3R | Texas | Blue-Cross Blue-Shield of Texas |
| M3S | Illinois | Blue-Cross Blue-Shield of Illinois |
| M3T | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| M3U | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M3V | Arizona | Blue-Cross Blue-Shield of Arizona |
| M3W | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M3X | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M3Y | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| M3Z | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| M4A | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| M4B | Pennsylvania | Highmark Blue-Shield of Pennsylvania |
| M4C | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| M4D | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M4E | Texas | Blue-Cross Blue-Shield of Texas |
| M4F | Texas | Blue-Cross Blue-Shield of Texas |
| M4G | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M4H | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| M4I | - | Unallocated/Not Assigned |
| M4J | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| M4K | Arizona | Blue-Cross Blue-Shield of Arizona |
| M4L | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| M4M | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| M4N | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M4O | - | Unallocated/Not Assigned |
| M4P | Texas | Blue-Cross Blue-Shield of Texas |
| M4Q | Michigan | Blue-Cross Blue-Shield of Michigan |
| M4R | New York (Northeastern) | Blue-Shield of Northeastern New York |
| M4S | Illinois | Blue-Cross Blue-Shield of Illinois |
| M4T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M4U | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| M4V | North Dakota | Blue-Cross Blue-Shield of North Dakota |
| M4W | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M4X | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M4Y | Idaho | Blue-Cross of Idaho |
| M4Z | Texas | Blue-Cross Blue-Shield of Texas |
| M5A | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| M5B | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| M5C | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| M5D | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| M5E | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| M5F | Texas | Blue-Cross Blue-Shield of Texas |
| M5G | Michigan | Blue-Cross Blue-Shield of Michigan |
| M5H | Texas | Blue-Cross Blue-Shield of Texas |
| M5I | California | Anthem Blue-Cross |
| M5J | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M5K | Illinois | Blue-Cross Blue-Shield of Illinois |
| M5L | Pennsylvania | Independence Blue-Cross of Pennsylvania |
| M5M | Texas | Blue-Cross Blue-Shield of Texas |
| M5N | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| M5O | - | Unallocated/Not Assigned |
| M5P | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M5Q | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| M5R | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| M5S | Texas | Blue-Cross Blue-Shield of Texas |
| M5T | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| M5U | California | Anthem Blue-Cross |
| M5V | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M5W | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M5X | Illinois | Blue-Cross Blue-Shield of Illinois |
| M5Y | Oklahoma | Blue-Cross Blue-Shield of Oklahoma |
| M5Z | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| M6A | Texas | Blue-Cross Blue-Shield of Texas |
| M6B | New Hampshire | Anthem Blue-Cross Blue-Shield of New Hampshire |
| M6C | New York | Empire Blue-Cross Blue-Shield of New York |
| M6D | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M6E | New York | Empire Blue-Cross Blue-Shield of New York |
| M6F | Texas | Blue-Cross Blue-Shield of Texas |
| M6G | New York | Empire Blue-Cross Blue-Shield of New York |
| M6H | New York | Empire Blue-Cross Blue-Shield of New York |
| M6I | - | Unallocated/Not Assigned |
| M6J | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M6K | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M6L | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M6M | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| M6N | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| M6O | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M6P | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M6Q | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| M6R | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M6S | Illinois | Blue-Cross Blue-Shield of Illinois |
| M6T | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M6U | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| M6V | Nevada | Anthem Blue-Cross Blue-Shield of Nevada |
| M6W | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M6X | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| M6Y | New York | Empire Blue-Cross Blue-Shield of New York |
| M6Z | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| M7A | California | Anthem Blue-Cross |
| M7B | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| M7C | New York | Empire Blue-Cross Blue-Shield of New York |
| M7D | North Dakota | Blue-Cross Blue-Shield of North Dakota |
| M7E | California | Anthem Blue-Cross |
| M7F | Texas | Blue-Cross Blue-Shield of Texas |
| M7G | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M7H | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M7I | - | Unallocated/Not Assigned |
| M7J | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M7K | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M7L | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M7M | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| M7N | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M7O | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M7P | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| M7Q | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| M7R | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M7S | Illinois | Blue-Cross Blue-Shield of Illinois |
| M7T | California | Anthem Blue-Cross |
| M7U | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M7V | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| M7W | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M7X | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| M7Y | - | Unallocated/Not Assigned |
| M7Z | Maine | Anthem Blue-Cross Blue-Shield of Maine |
| M8A | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| M8B | Illinois | Blue-Cross Blue-Shield of Illinois |
| M8C | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| M8D | Maine | Anthem Blue-Cross Blue-Shield of Maine |
| M8E | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M8F | Texas | Blue-Cross Blue-Shield of Texas |
| M8G | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M8H | New York | Empire Blue-Cross Blue-Shield of New York |
| M8I | - | Unallocated/Not Assigned |
| M8J | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M8K | Texas | Blue-Cross Blue-Shield of Texas |
| M8L | California | Anthem Blue-Cross |
| M8M | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M8N | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M8O | - | Unallocated/Not Assigned |
| M8P | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| M8Q | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| M8R | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M8S | Illinois | Blue-Cross Blue-Shield of Illinois |
| M8T | Illinois | Blue-Cross Blue-Shield of Illinois |
| M8U | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M8V | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| M8W | Maine | Anthem Blue-Cross Blue-Shield of Maine |
| M8X | New Hampshire | Anthem Blue-Cross Blue-Shield of New Hampshire |
| M8Y | Texas | Blue-Cross Blue-Shield of Texas |
| M8Z | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M9A | New York | Empire Blue-Cross Blue-Shield of New York |
| M9B | Illinois | Blue-Cross Blue-Shield of Illinois |
| M9C | New York | Empire Blue-Cross Blue-Shield of New York |
| M9D | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M9E | Maine | Anthem Blue-Cross Blue-Shield of Maine |
| M9F | Texas | Blue-Cross Blue-Shield of Texas |
| M9G | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M9H | Illinois | Blue-Cross Blue-Shield of Illinois |
| M9I | - | Unallocated/Not Assigned |
| M9J | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M9K | Texas | Blue-Cross Blue-Shield of Texas |
| M9L | Texas | Blue-Cross Blue-Shield of Texas |
| M9M | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M9N | California | Anthem Blue-Cross |
| M9O | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M9P | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| M9Q | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| M9R | California | Anthem Blue-Cross |
| M9S | Illinois | Blue-Cross Blue-Shield of Illinois |
| M9T | Texas | Blue-Cross Blue-Shield of Texas |
| M9U | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| M9V | - | Unallocated/Not Assigned |
| M9W | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| M9X | - | Couple Health |
| M9Y | - | Couple Health |
| M9Z | - | Couple Health |
Hi, I’m Hammad Butt the founder and content creator behind BCBS Prefix List. I’m a U.S. Citizen with over 10 years of hands-on experience in the medical billing and healthcare administration industry. Throughout my career, I’ve worked with private practices, urgent care centers, and billing companies across the United States, helping them navigate complex insurance systems especially Blue Cross Blue Shield (BCBS) claims and verifications.