| X2A | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X2B | Idaho | Blue-Cross of Idaho |
| X2C | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X2D | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X2E | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X2F | California | Anthem Blue-Cross |
| X2G | - | Prefix Unallocated/Not Assigned |
| X2H | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| X2I | - | Prefix Unallocated/Not Assigned |
| X2J | - | Prefix Unallocated/Not Assigned |
| X2K | - | Prefix Unallocated/Not Assigned |
| X2L | - | Prefix Unallocated/Not Assigned |
| X2M | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| X2N | - | Prefix Unallocated/Not Assigned |
| X2O | - | Prefix Unallocated/Not Assigned |
| X2P | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| X2Q | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| X2R | Illinois | Blue-Cross Blue-Shield of Illinois |
| X2S | Illinois | Blue-Cross Blue-Shield of Illinois |
| X2T | Illinois | Blue-Cross Blue-Shield of Illinois |
| X2U | Illinois | Blue-Cross Blue-Shield of Illinois |
| X2V | - | Prefix Unallocated/Not Assigned |
| X2W | - | Prefix Unallocated/Not Assigned |
| X2X | - | Prefix Unallocated/Not Assigned |
| X2Y | - | Prefix Unallocated/Not Assigned |
| X2Z | - | Prefix Unallocated/Not Assigned |
| X3A | New Hampshire | Anthem Blue-Cross Blue-Shield of New Hampshire |
| X3B | New Hampshire | Anthem Blue-Cross Blue-Shield of New Hampshire |
| X3C | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| X3D | New Hampshire | Anthem Blue-Cross Blue-Shield of New Hampshire |
| X3E | - | Prefix Unallocated/Not Assigned |
| X3F | New Hampshire | Anthem Blue-Cross Blue-Shield of New Hampshire |
| X3G | New Hampshire | Anthem Blue-Cross Blue-Shield of New Hampshire |
| X3H | South Dakota/Iowa | Wellmark Blue-Cross Blue-Shield |
| X3I | - | Prefix Unallocated/Not Assigned |
| X3J | - | Prefix Unallocated/Not Assigned |
| X3K | - | Prefix Unallocated/Not Assigned |
| X3L | - | Prefix Unallocated/Not Assigned |
| X3M | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| X3N | - | Prefix Unallocated/Not Assigned |
| X3O | - | Prefix Unallocated/Not Assigned |
| X3P | - | Prefix Unallocated/Not Assigned |
| X3Q | - | Prefix Unallocated/Not Assigned |
| X3R | - | Prefix Unallocated/Not Assigned |
| X3S | - | Prefix Unallocated/Not Assigned |
| X3T | California | Anthem Blue-Cross |
| X3U | - | Prefix Unallocated/Not Assigned |
| X3V | - | Prefix Unallocated/Not Assigned |
| X3W | - | Prefix Unallocated/Not Assigned |
| X3X | - | Prefix Unallocated/Not Assigned |
| X3Y | - | Prefix Unallocated/Not Assigned |
| X3Z | - | Prefix Unallocated/Not Assigned |
| X4A | California | Anthem Blue-Cross |
| X4B | - | Prefix Unallocated/Not Assigned |
| X4C | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| X4D | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X4E | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| X4F | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| X4G | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| X4H | California | Anthem Blue-Cross |
| X4I | - | Prefix Unallocated/Not Assigned |
| X4J | - | Prefix Unallocated/Not Assigned |
| X4K | - | Prefix Unallocated/Not Assigned |
| X4L | - | Prefix Unallocated/Not Assigned |
| X4M | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| X4N | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| X4O | - | Prefix Unallocated/Not Assigned |
| X4P | - | Prefix Unallocated/Not Assigned |
| X4Q | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| X4R | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| X4S | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| X4T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| X4U | - | Prefix Unallocated/Not Assigned |
| X4V | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| X4W | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| X4X | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| X4Y | - | Prefix Unallocated/Not Assigned |
| X4Z | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| X5A | California | Anthem Blue-Cross |
| X5B | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X5C | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| X5D | - | Prefix Unallocated/Not Assigned |
| X5E | - | Prefix Unallocated/Not Assigned |
| X5F | - | Prefix Unallocated/Not Assigned |
| X5G | - | Prefix Unallocated/Not Assigned |
| X5H | - | Prefix Unallocated/Not Assigned |
| X5I | - | Prefix Unallocated/Not Assigned |
| X5J | - | Prefix Unallocated/Not Assigned |
| X5K | - | Prefix Unallocated/Not Assigned |
| X5L | - | Prefix Unallocated/Not Assigned |
| X5M | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| X5N | - | Prefix Unallocated/Not Assigned |
| X5O | - | Prefix Unallocated/Not Assigned |
| X5P | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X5Q | - | Prefix Unallocated/Not Assigned |
| X5R | - | Prefix Unallocated/Not Assigned |
| X5S | - | Prefix Unallocated/Not Assigned |
| X5T | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X5U | - | Prefix Unallocated/Not Assigned |
| X5V | - | Prefix Unallocated/Not Assigned |
| X5W | - | Prefix Unallocated/Not Assigned |
| X5X | - | Prefix Unallocated/Not Assigned |
| X5Y | - | Prefix Unallocated/Not Assigned |
| X5Z | - | Prefix Unallocated/Not Assigned |
| X6A | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| X6B | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6C | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6D | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6E | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6F | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| X6G | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X6H | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6I | - | Prefix Unallocated/Not Assigned |
| X6J | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6K | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6L | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6M | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| X6N | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6O | - | Prefix Unallocated/Not Assigned |
| X6P | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6Q | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6R | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6S | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6T | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X6U | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6V | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| X6W | - | Prefix Unallocated/Not Assigned |
| X6X | - | Prefix Unallocated/Not Assigned |
| X6Y | - | Prefix Unallocated/Not Assigned |
| X6Z | - | Prefix Unallocated/Not Assigned |
| X7A | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7B | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7C | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7D | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7E | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7F | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7G | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7H | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7I | - | Prefix Unallocated/Not Assigned |
| X7J | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7K | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7L | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7M | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7N | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7O | - | Prefix Unallocated/Not Assigned |
| X7P | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| X7Q | - | Prefix Unallocated/Not Assigned |
| X7R | - | Prefix Unallocated/Not Assigned |
| X7S | - | Prefix Unallocated/Not Assigned |
| X7T | - | Prefix Unallocated/Not Assigned |
| X7U | - | Prefix Unallocated/Not Assigned |
| X7V | - | Prefix Unallocated/Not Assigned |
| X7W | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| X7X | - | Prefix Unallocated/Not Assigned |
| X7Y | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| X7Z | - | Prefix Unallocated/Not Assigned |
| X8A | California | Anthem Blue-Cross |
| X8B | California | Anthem Blue-Cross |
| X8C | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| X8D | - | Prefix Unallocated/Not Assigned |
| X8E | - | Prefix Unallocated/Not Assigned |
| X8F | - | Prefix Unallocated/Not Assigned |
| X8G | - | Prefix Unallocated/Not Assigned |
| X8H | - | Prefix Unallocated/Not Assigned |
| X8I | - | Prefix Unallocated/Not Assigned |
| X8J | - | Prefix Unallocated/Not Assigned |
| X8K | - | Prefix Unallocated/Not Assigned |
| X8L | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| X8M | California | Anthem Blue-Cross |
| X8N | - | Prefix Unallocated/Not Assigned |
| X8O | - | Prefix Unallocated/Not Assigned |
| X8P | - | Prefix Unallocated/Not Assigned |
| X8Q | - | Prefix Unallocated/Not Assigned |
| X8R | - | Prefix Unallocated/Not Assigned |
| X8S | California | Anthem Blue-Cross |
| X8T | - | Prefix Unallocated/Not Assigned |
| X8U | - | Prefix Unallocated/Not Assigned |
| X8V | - | Prefix Unallocated/Not Assigned |
| X8W | - | Prefix Unallocated/Not Assigned |
| X8X | - | Prefix Unallocated/Not Assigned |
| X8Y | - | Prefix Unallocated/Not Assigned |
| X8Z | - | Prefix Unallocated/Not Assigned |
| X9A | California | Anthem Blue-Cross |
| X9B | California | Anthem Blue-Cross |
| X9C | - | Prefix Unallocated/Not Assigned |
| X9D | California | Anthem Blue-Cross |
| X9E | - | Prefix Unallocated/Not Assigned |
| X9F | - | Prefix Unallocated/Not Assigned |
| X9G | California | Anthem Blue-Cross |
| X9H | - | Prefix Unallocated/Not Assigned |
| X9I | - | Prefix Unallocated/Not Assigned |
| X9J | - | Prefix Unallocated/Not Assigned |
| X9K | - | Prefix Unallocated/Not Assigned |
| X9L | - | Prefix Unallocated/Not Assigned |
| X9M | California | Anthem Blue-Cross |
| X9N | - | Prefix Unallocated/Not Assigned |
| X9O | - | Prefix Unallocated/Not Assigned |
| X9P | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| X9Q | - | Prefix Unallocated/Not Assigned |
| X9R | - | Prefix Unallocated/Not Assigned |
| X9S | California | Anthem Blue-Cross |
| X9T | - | Prefix Unallocated/Not Assigned |
| X9U | - | Prefix Unallocated/Not Assigned |
| X9V | - | Prefix Unallocated/Not Assigned |
| X9W | - | Prefix Unallocated/Not Assigned |
| X9X | - | Prefix Unallocated/Not Assigned |
| X9Y | - | Prefix Unallocated/Not Assigned |
| X9Z | - | Prefix Unallocated/Not Assigned |