| W2A | New York (Northeastern) | Blue-Shield of Northeastern New York |
| W2B | Illinois | Blue-Cross Blue-Shield of Illinois |
| W2C | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W2D | West Virginia | Highmark Blue-Cross Blue-Shield of West Virginia |
| W2E | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| W2F | Illinois | Blue-Cross Blue-Shield of Illinois |
| W2G | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W2H | California | Anthem Blue-Cross |
| W2I | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| W2J | West Virginia | Highmark Blue-Cross Blue-Shield of West Virginia |
| W2K | Arkansas | Arkansas Blue-Cross Blue-Shield |
| W2L | Illinois | Blue-Cross Blue-Shield of Illinois |
| W2M | Illinois | Blue-Cross Blue-Shield of Illinois |
| W2N | Arkansas | Arkansas Blue-Cross Blue-Shield |
| W2O | * | Prefix Unallocated/Not Assigned |
| W2P | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W2Q | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| W2R | West Virginia | Highmark Blue-Cross Blue-Shield of West Virginia |
| W2S | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W2T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W2U | West Virginia | Highmark Blue-Cross Blue-Shield of West Virginia |
| W2V | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| W2W | Arkansas | Arkansas Blue-Cross Blue-Shield |
| W2X | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| W2Y | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| W2Z | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| W3A | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| W3B | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| W3C | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W3D | Nevada | Anthem Blue-Cross Blue-Shield of Nevada |
| W3E | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| W3F | California | Anthem Blue-Cross |
| W3G | Texas | Blue-Cross Blue-Shield of Texas |
| W3H | Alaska | Premera Blue-Cross of Alaska |
| W3I | * | Prefix Unallocated/Not Assigned |
| W3J | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W3K | Alaska | Premera Blue-Cross of Alaska |
| W3L | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| W3M | Illinois | Blue-Cross Blue-Shield of Illinois |
| W3N | California | Anthem Blue-Cross |
| W3O | * | Prefix Unallocated/Not Assigned |
| W3P | New York | Empire Blue-Cross Blue-Shield of New York |
| W3Q | California | Anthem Blue-Cross |
| W3R | Texas | Blue-Cross Blue-Shield of Texas |
| W3S | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W3T | Arkansas | Arkansas Blue-Cross Blue-Shield |
| W3U | West Virginia | Highmark Blue-Cross Blue-Shield of West Virginia |
| W3V | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W3W | New York | Empire Blue-Cross Blue-Shield of New York |
| W3X | New York | Empire Blue-Cross Blue-Shield of New York |
| W3Y | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| W3Z | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W4A | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| W4B | Illinois | Blue-Cross Blue-Shield of Illinois |
| W4C | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| W4D | * | Prefix Unallocated/Not Assigned |
| W4E | * | Prefix Unallocated/Not Assigned |
| W4F | Texas | Blue-Cross Blue-Shield of Texas |
| W4G | Texas | Blue-Cross Blue-Shield of Texas |
| W4H | Rhode Island | Blue-Cross Blue-Shield of Rhode Island |
| W4I | * | Prefix Unallocated/Not Assigned |
| W4J | Texas | Blue-Cross Blue-Shield of Texas |
| W4K | Texas | Blue-Cross Blue-Shield of Texas |
| W4L | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| W4M | Texas | Blue-Cross Blue-Shield of Texas |
| W4N | Texas | Blue-Cross Blue-Shield of Texas |
| W4O | * | Prefix Unallocated/Not Assigned |
| W4P | Texas | Blue-Cross Blue-Shield of Texas |
| W4Q | * | Prefix Unallocated/Not Assigned |
| W4R | Texas | Blue-Cross Blue-Shield of Texas |
| W4S | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| W4T | Alaska | Premera Blue-Cross of Alaska |
| W4U | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| W4V | Texas | Blue-Cross Blue-Shield of Texas |
| W4W | Texas | Blue-Cross Blue-Shield of Texas |
| W4X | Texas | Blue-Cross Blue-Shield of Texas |
| W4Y | Texas | Blue-Cross Blue-Shield of Texas |
| W4Z | Texas | Blue-Cross Blue-Shield of Texas |
| W5A | Texas | Blue-Cross Blue-Shield of Texas |
| W5B | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W5C | Vermont | Blue-Cross of Vermont |
| W5D | * | Prefix Unallocated/Not Assigned |
| W5E | * | Prefix Unallocated/Not Assigned |
| W5F | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W5G | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| W5H | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| W5I | * | Prefix Unallocated/Not Assigned |
| W5J | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| W5K | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| W5L | * | Prefix Unallocated/Not Assigned |
| W5M | Illinois | Blue-Cross Blue-Shield of Illinois |
| W5N | * | Prefix Unallocated/Not Assigned |
| W5O | * | Prefix Unallocated/Not Assigned |
| W5P | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| W5Q | * | Prefix Unallocated/Not Assigned |
| W5R | * | Prefix Unallocated/Not Assigned |
| W5S | * | Prefix Unallocated/Not Assigned |
| W5T | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| W5U | * | Prefix Unallocated/Not Assigned |
| W5V | * | Prefix Unallocated/Not Assigned |
| W5W | * | Prefix Unallocated/Not Assigned |
| W5X | * | Prefix Unallocated/Not Assigned |
| W5Y | * | Prefix Unallocated/Not Assigned |
| W5Z | * | Prefix Unallocated/Not Assigned |
| W6A | Texas | Blue-Cross Blue-Shield of Texas |
| W6B | Texas | Blue-Cross Blue-Shield of Texas |
| W6C | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| W6D | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| W6E | * | Prefix Unallocated/Not Assigned |
| W6F | New Hampshire | Anthem Blue-Cross Blue-Shield of New Hampshire |
| W6G | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W6H | California | Anthem Blue-Cross |
| W6I | * | Prefix Unallocated/Not Assigned |
| W6J | Delaware | Highmark Blue-Cross Blue-Shield of Delaware |
| W6K | * | Prefix Unallocated/Not Assigned |
| W6L | Delaware | Highmark Blue-Cross Blue-Shield of Delaware |
| W6M | New York | Empire Blue-Cross Blue-Shield of New York |
| W6N | * | Prefix Unallocated/Not Assigned |
| W6O | * | Prefix Unallocated/Not Assigned |
| W6P | New York | Empire Blue-Cross Blue-Shield of New York |
| W6Q | * | Prefix Unallocated/Not Assigned |
| W6R | New York | Empire Blue-Cross Blue-Shield of New York |
| W6S | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| W6T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W6U | New York | Empire Blue-Cross Blue-Shield of New York |
| W6V | New York | Empire Blue-Cross Blue-Shield of New York |
| W6W | New York | Empire Blue-Cross Blue-Shield of New York |
| W6X | Maine | Anthem Blue-Cross Blue-Shield of Maine |
| W6Y | New York | Empire Blue-Cross Blue-Shield of New York |
| W6Z | * | Prefix Unallocated/Not Assigned |
| W7A | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| W7B | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| W7C | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| W7D | Illinois | Blue-Cross Blue-Shield of Illinois |
| W7E | * | Prefix Unallocated/Not Assigned |
| W7F | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W7G | Illinois | Blue-Cross Blue-Shield of Illinois |
| W7H | Illinois | Blue-Cross Blue-Shield of Illinois |
| W7I | * | Prefix Unallocated/Not Assigned |
| W7J | * | Prefix Unallocated/Not Assigned |
| W7K | * | Prefix Unallocated/Not Assigned |
| W7L | * | Prefix Unallocated/Not Assigned |
| W7M | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| W7N | * | Prefix Unallocated/Not Assigned |
| W7O | * | Prefix Unallocated/Not Assigned |
| W7P | New York | Empire Blue-Cross Blue-Shield of New York |
| W7Q | * | Prefix Unallocated/Not Assigned |
| W7R | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| W7S | California | Anthem Blue-Cross |
| W7T | Illinois | Blue-Cross Blue-Shield of Illinois |
| W7U | * | Prefix Unallocated/Not Assigned |
| W7V | * | Prefix Unallocated/Not Assigned |
| W7W | New York | Empire Blue-Cross Blue-Shield of New York |
| W7X | * | Prefix Unallocated/Not Assigned |
| W7Y | * | Prefix Unallocated/Not Assigned |
| W7Z | * | Prefix Unallocated/Not Assigned |
| W8A | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| W8B | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| W8C | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| W8D | Illinois | Blue-Cross Blue-Shield of Illinois |
| W8E | * | Prefix Unallocated/Not Assigned |
| W8F | * | Prefix Unallocated/Not Assigned |
| W8G | * | Prefix Unallocated/Not Assigned |
| W8H | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| W8I | * | Prefix Unallocated/Not Assigned |
| W8J | * | Prefix Unallocated/Not Assigned |
| W8K | * | Prefix Unallocated/Not Assigned |
| W8L | * | Prefix Unallocated/Not Assigned |
| W8M | * | Prefix Unallocated/Not Assigned |
| W8N | * | Prefix Unallocated/Not Assigned |
| W8O | * | Prefix Unallocated/Not Assigned |
| W8P | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W8Q | * | Prefix Unallocated/Not Assigned |
| W8R | * | Prefix Unallocated/Not Assigned |
| W8S | * | Prefix Unallocated/Not Assigned |
| W8T | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| W8U | Michigan | Blue-Cross Blue Shield of Michigan |
| W8V | * | Prefix Unallocated/Not Assigned |
| W8W | * | Prefix Unallocated/Not Assigned |
| W8X | * | Prefix Unallocated/Not Assigned |
| W8Y | * | Prefix Unallocated/Not Assigned |
| W8Z | * | Prefix Unallocated/Not Assigned |
| W9A | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W9B | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| W9C | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W9D | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| W9E | * | Prefix Unallocated/Not Assigned |
| W9F | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W9G | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| W9H | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| W9I | * | Prefix Unallocated/Not Assigned |
| W9J | * | Prefix Unallocated/Not Assigned |
| W9K | * | Prefix Unallocated/Not Assigned |
| W9L | * | Prefix Unallocated/Not Assigned |
| W9M | Illinois | Blue-Cross Blue-Shield of Illinois |
| W9N | * | Prefix Unallocated/Not Assigned |
| W9O | * | Prefix Unallocated/Not Assigned |
| W9P | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| W9Q | * | Prefix Unallocated/Not Assigned |
| W9R | * | Prefix Unallocated/Not Assigned |
| W9S | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| W9T | * | Prefix Unallocated/Not Assigned |
| W9U | * | Prefix Unallocated/Not Assigned |
| W9V | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| W9W | * | Prefix Unallocated/Not Assigned |
| W9X | Michigan | Blue-Cross Blue Shield of Michigan |
| W9Y | * | Prefix Unallocated/Not Assigned |
| W9Z | * | Prefix Unallocated/Not Assigned |
