| U2A | Texas | Blue-Cross Blue-Shield of Texas |
| U2B | New York | Empire Blue-Cross Blue-Shield of New York |
| U2C | New York | Empire Blue-Cross Blue-Shield of New York |
| U2D | New York | Empire Blue-Cross Blue-Shield of New York |
| U2E | New York | Empire Blue-Cross Blue-Shield of New York |
| U2F | Illinois | Blue-Cross Blue-Shield of Illinois |
| U2G | Arkansas | Arkansas Blue-Cross Blue-Shield |
| U2H | New York | Empire Blue-Cross Blue-Shield of New York |
| U2I | New York | Empire Blue-Cross Blue-Shield of New York |
| U2J | New York | Empire Blue-Cross Blue-Shield of New York |
| U2K | New York | Empire Blue-Cross Blue-Shield of New York |
| U2L | New York | Empire Blue-Cross Blue-Shield of New York |
| U2M | Oklahoma | Blue-Cross Blue-Shield of Oklahoma |
| U2N | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U2O | * | Prefix Unallocated/Not Assigned |
| U2P | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U2Q | New York | Empire Blue-Cross Blue-Shield of New York |
| U2R | New York | Empire Blue-Cross Blue-Shield of New York |
| U2S | Texas | Blue-Cross Blue-Shield of Texas |
| U2T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U2U | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U2V | New York | Empire Blue-Cross Blue-Shield of New York |
| U2W | New York | Empire Blue-Cross Blue-Shield of New York |
| U2X | New York | Empire Blue-Cross Blue-Shield of New York |
| U2Y | New York | Empire Blue-Cross Blue-Shield of New York |
| U2Z | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| U3A | California | Anthem Blue-Cross |
| U3B | California | Anthem Blue-Cross |
| U3C | California | Anthem Blue-Cross |
| U3D | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| U3E | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| U3F | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| U3G | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| U3H | New York | Empire Blue-Cross Blue-Shield of New York |
| U3I | * | Prefix Unallocated/Not Assigned |
| U3J | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U3K | * | Prefix Unallocated/Not Assigned |
| U3L | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U3M | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| U3N | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U3O | * | Prefix Unallocated/Not Assigned |
| U3P | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| U3Q | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U3R | Texas | Blue-Cross Blue-Shield of Texas |
| U3S | Illinois | Blue-Cross Blue-Shield of Illinois |
| U3T | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U3U | Illinois | Blue-Cross Blue-Shield of Illinois |
| U3V | Illinois | Blue-Cross Blue-Shield of Illinois |
| U3W | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U3X | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U3Y | Illinois | Blue-Cross Blue-Shield of Illinois |
| U3Z | California | Anthem Blue-Cross |
| U4A | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| U4B | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U4C | New York | Empire Blue-Cross Blue-Shield of New York |
| U4D | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| U4E | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U4F | Illinois | Blue-Cross Blue-Shield of Illinois |
| U4G | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| U4H | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| U4I | * | Prefix Unallocated/Not Assigned |
| U4J | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| U4K | California | Anthem Blue-Cross |
| U4L | California | Anthem Blue-Cross |
| U4M | Illinois | Blue-Cross Blue-Shield of Illinois |
| U4N | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U4O | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U4P | Illinois | Blue-Cross Blue-Shield of Illinois |
| U4Q | * | Prefix Unallocated/Not Assigned |
| U4R | Texas | Blue-Cross Blue-Shield of Texas |
| U4S | Texas | Blue-Cross Blue-Shield of Texas |
| U4T | Illinois | Blue-Cross Blue-Shield of Illinois |
| U4U | California | Anthem Blue-Cross |
| U4V | * | Prefix Unallocated/Not Assigned |
| U4W | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| U4X | * | Prefix Unallocated/Not Assigned |
| U4Y | New York | Empire Blue-Cross Blue-Shield of New York |
| U4Z | * | Prefix Unallocated/Not Assigned |
| U5A | Alabama | Blue-Cross Blue-Shield of Alabama |
| U5B | * | Prefix Unallocated/Not Assigned |
| U5C | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| U5D | * | Prefix Unallocated/Not Assigned |
| U5E | * | Prefix Unallocated/Not Assigned |
| U5F | * | Prefix Unallocated/Not Assigned |
| U5G | * | Prefix Unallocated/Not Assigned |
| U5H | * | Prefix Unallocated/Not Assigned |
| U5I | * | Prefix Unallocated/Not Assigned |
| U5J | * | Prefix Unallocated/Not Assigned |
| U5K | * | Prefix Unallocated/Not Assigned |
| U5L | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| U5M | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| U5N | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U5O | * | Prefix Unallocated/Not Assigned |
| U5P | Alabama | Blue-Cross Blue-Shield of Alabama |
| U5Q | * | Prefix Unallocated/Not Assigned |
| U5R | Texas | Blue-Cross Blue-Shield of Texas |
| U5S | * | Prefix Unallocated/Not Assigned |
| U5T | * | Prefix Unallocated/Not Assigned |
| U5U | * | Prefix Unallocated/Not Assigned |
| U5V | * | Prefix Unallocated/Not Assigned |
| U5W | * | Prefix Unallocated/Not Assigned |
| U5X | * | Prefix Unallocated/Not Assigned |
| U5Y | * | Prefix Unallocated/Not Assigned |
| U5Z | * | Prefix Unallocated/Not Assigned |
| U6A | Texas | Blue-Cross Blue-Shield of Texas |
| U6B | * | Prefix Unallocated/Not Assigned |
| U6C | California | Anthem Blue-Cross |
| U6D | * | Prefix Unallocated/Not Assigned |
| U6E | * | Prefix Unallocated/Not Assigned |
| U6F | * | Prefix Unallocated/Not Assigned |
| U6G | * | Prefix Unallocated/Not Assigned |
| U6H | * | Prefix Unallocated/Not Assigned |
| U6I | * | Prefix Unallocated/Not Assigned |
| U6J | * | Prefix Unallocated/Not Assigned |
| U6K | * | Prefix Unallocated/Not Assigned |
| U6L | * | Prefix Unallocated/Not Assigned |
| U6M | New York | Empire Blue-Cross Blue-Shield of New York |
| U6N | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U6O | * | Prefix Unallocated/Not Assigned |
| U6P | Illinois | Blue-Cross Blue-Shield of Illinois |
| U6Q | * | Prefix Unallocated/Not Assigned |
| U6R | Texas | Blue-Cross Blue-Shield of Texas |
| U6S | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U6T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U6U | * | Prefix Unallocated/Not Assigned |
| U6V | * | Prefix Unallocated/Not Assigned |
| U6W | * | Prefix Unallocated/Not Assigned |
| U6X | * | Prefix Unallocated/Not Assigned |
| U6Y | * | Prefix Unallocated/Not Assigned |
| U6Z | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| U7A | Texas | Blue-Cross Blue-Shield of Texas |
| U7B | * | Prefix Unallocated/Not Assigned |
| U7C | * | Prefix Unallocated/Not Assigned |
| U7D | California | Anthem Blue-Cross |
| U7E | * | Prefix Unallocated/Not Assigned |
| U7F | * | Prefix Unallocated/Not Assigned |
| U7G | New York | Empire Blue-Cross Blue-Shield of New York |
| U7H | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U7I | * | Prefix Unallocated/Not Assigned |
| U7J | * | Prefix Unallocated/Not Assigned |
| U7K | * | Prefix Unallocated/Not Assigned |
| U7L | * | Prefix Unallocated/Not Assigned |
| U7M | New York | Empire Blue-Cross Blue-Shield of New York |
| U7N | * | Prefix Unallocated/Not Assigned |
| U7O | * | Prefix Unallocated/Not Assigned |
| U7P | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U7Q | * | Prefix Unallocated/Not Assigned |
| U7R | Texas | Blue-Cross Blue-Shield of Texas |
| U7S | California | Anthem Blue-Cross |
| U7T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U7U | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U7V | * | Prefix Unallocated/Not Assigned |
| U7W | * | Prefix Unallocated/Not Assigned |
| U7X | * | Prefix Unallocated/Not Assigned |
| U7Y | * | Prefix Unallocated/Not Assigned |
| U7Z | * | Prefix Unallocated/Not Assigned |
| U8A | Texas Blue-Cross Blue-Shield of Texas |
| U8B | * | Prefix Unallocated/Not Assigned |
| U8C | Illinois | Blue-Cross Blue-Shield of Illinois |
| U8D | * | Prefix Unallocated/Not Assigned |
| U8E | * | Prefix Unallocated/Not Assigned |
| U8F | * | Prefix Unallocated/Not Assigned |
| U8G | Illinois | Blue-Cross Blue-Shield of Illinois |
| U8H | * | Prefix Unallocated/Not Assigned |
| U8I | * | Prefix Unallocated/Not Assigned |
| U8J | * | Prefix Unallocated/Not Assigned |
| U8K | * | Prefix Unallocated/Not Assigned |
| U8L | * | Prefix Unallocated/Not Assigned |
| U8M | * | Prefix Unallocated/Not Assigned |
| U8N | * | Prefix Unallocated/Not Assigned |
| U8O | * | Prefix Unallocated/Not Assigned |
| U8P | * | Prefix Unallocated/Not Assigned |
| U8Q | * | Prefix Unallocated/Not Assigned |
| U8R | Texas | Blue-Cross Blue-Shield of Texas |
| U8S | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| U8T | * | Prefix Unallocated/Not Assigned |
| U8U | * | Prefix Unallocated/Not Assigned |
| U8V | * | Prefix Unallocated/Not Assigned |
| U8W | * | Prefix Unallocated/Not Assigned |
| U8X | * | Prefix Unallocated/Not Assigned |
| U8Y | * | Prefix Unallocated/Not Assigned |
| U8Z | * | Prefix Unallocated/Not Assigned |
| U9A | California | Anthem Blue-Cross |
| U9B | Texas | Blue-Cross Blue-Shield of Texas |
| U9C | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| U9D | * | Prefix Unallocated/Not Assigned |
| U9E | * | Prefix Unallocated/Not Assigned |
| U9F | * | Prefix Unallocated/Not Assigned |
| U9G | * | Prefix Unallocated/Not Assigned |
| U9H | * | Prefix Unallocated/Not Assigned |
| U9I | * | Prefix Unallocated/Not Assigned |
| U9J | * | Prefix Unallocated/Not Assigned |
| U9K | * | Prefix Unallocated/Not Assigned |
| U9L | * | Prefix Unallocated/Not Assigned |
| U9M | Illinois | Blue-Cross Blue-Shield of Illinois |
| U9N | New York | Empire Blue-Cross Blue-Shield of New York |
| U9O | * | Prefix Unallocated/Not Assigned |
| U9P | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U9Q | * | Prefix Unallocated/Not Assigned |
| U9R | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| U9S | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U9T | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| U9U | * | Prefix Unallocated/Not Assigned |
| U9V | * | Prefix Unallocated/Not Assigned |
| U9W | * | Prefix Unallocated/Not Assigned |
| U9X | * | Prefix Unallocated/Not Assigned |
| U9Y | * | Prefix Unallocated/Not Assigned |
| U9Z | * | Prefix Unallocated/Not Assigned |
