| S2A | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| S2B | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2C | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2D | Texas | Blue-Cross Blue-Shield of Texas |
| S2E | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2F | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2G | Texas | Blue-Cross Blue-Shield of Texas |
| S2H | Alabama | Blue-Cross Blue-Shield of Alabama |
| S2I | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| S2J | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2K | Texas | Blue-Cross Blue-Shield of Texas |
| S2L | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2M | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S2N | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2O | North Carolina | Blue-Cross Blue-Shield of North Carolina |
| S2P | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2Q | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| S2R | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2S | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S2T | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2U | California | Anthem Blue-Cross |
| S2V | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2W | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2X | Texas | Blue-Cross Blue-Shield of Texas |
| S2Y | Illinois | Blue-Cross Blue-Shield of Illinois |
| S2Z | Texas | Blue-Cross Blue-Shield of Texas |
| S3A | New York (Northeastern) | Blue-Shield of Northeastern New York |
| S3B | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S3C | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S3D | Illinois | Blue-Cross Blue-Shield of Illinois |
| S3E | Illinois | Blue-Cross Blue-Shield of Illinois |
| S3F | Illinois | Blue-Cross Blue-Shield of Illinois |
| S3G | Alaska | Premera Blue-Cross of Alaska |
| S3H | Texas | Blue-Cross Blue-Shield of Texas |
| S3I | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| S3J | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| S3K | Texas | Blue-Cross Blue-Shield of Texas |
| S3L | Illinois | Blue-Cross Blue-Shield of Illinois |
| S3M | Illinois | Blue-Cross Blue-Shield of Illinois |
| S3N | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| S3O | Pennsylvania | Highmark Blue-Shield of Pennsylvania |
| S3P | Illinois | Blue-Cross Blue-Shield of Illinois |
| S3Q | California | Anthem Blue-Cross |
| S3R | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| S3S | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S3T | New York (Western) | Blue-Cross Blue-Shield of Western New York |
| S3U | Delaware | Highmark Blue-Cross Blue-Shield of Delaware |
| S3V | Pennsylvania | Highmark Blue-Shield of Pennsylvania |
| S3W | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| S3X | California | Anthem Blue-Cross |
| S3Y | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| S3Z | Arizona | Blue-Cross Blue-Shield of Arizona |
| S4A | Alaska | Premera Blue-Cross of Alaska |
| S4B | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S4C | Alaska | Premera Blue-Cross of Alaska |
| S4D | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S4E | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S4F | Illinois | Blue-Cross Blue-Shield of Illinois |
| S4G | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| S4H | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S4I | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S4J | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| S4K | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S4L | Illinois | Blue-Cross Blue-Shield of Illinois |
| S4M | Illinois | Blue-Cross Blue-Shield of Illinois |
| S4N | Illinois | Blue-Cross Blue-Shield of Illinois |
| S4O | - Prefix Unallocated/Not Assigned |
| S4P | Illinois | Blue-Cross Blue-Shield of Illinois |
| S4Q | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S4R | New York | Empire Blue-Cross Blue-Shield of New York |
| S4S | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S4T | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| S4U | Texas | Blue-Cross Blue-Shield of Texas |
| S4V | Alaska | Premera Blue-Cross of Alaska |
| S4W | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S4X | Texas | Blue-Cross Blue-Shield of Texas |
| S4Y | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S4Z | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| S5A | Texas | Blue-Cross Blue-Shield of Texas |
| S5B | Colorado | Anthem Blue-Cross Blue-Shield of Colorado |
| S5C | Massachusetts | Blue-Cross Blue-Shield of Massachusetts |
| S5D | California | Anthem Blue-Cross |
| S5E | Texas | Blue-Cross Blue-Shield of Texas |
| S5F | * | Prefix Unallocated/Not Assigned |
| S5G | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S5H | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S5I | * | Prefix Unallocated/Not Assigned |
| S5J | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| S5K | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| S5L | Illinois | Blue-Cross Blue-Shield of Illinois |
| S5M | Illinois | Blue-Cross Blue-Shield of Illinois |
| S5N | Texas | Blue-Cross Blue-Shield of Texas |
| S5O | * | Prefix Unallocated/Not Assigned |
| S5P | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| S5Q | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S5R | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| S5S | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S5T | Illinois | Blue-Cross Blue-Shield of Illinois |
| S5U | Texas | Blue-Cross Blue-Shield of Texas |
| S5V | Pennsylvania | Capital Blue-Cross of Pennsylvania |
| S5W | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S5X | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| S5Y | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| S5Z | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| S6A | Texas | Blue-Cross Blue-Shield of Texas |
| S6B | Illinois | Blue-Cross Blue-Shield of Illinois |
| S6C | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| S6D | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S6E | Texas | Blue-Cross Blue-Shield of Texas |
| S6F | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S6G | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
| S6H | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| S6I | * | Prefix Unallocated/Not Assigned |
| S6J | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| S6K | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| S6L | Texas | Blue-Cross Blue-Shield of Texas |
| S6M | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| S6N | Texas | Blue-Cross Blue-Shield of Texas |
| S6O | * | Prefix Unallocated/Not Assigned |
| S6P | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S6Q | New York | Empire Blue-Cross Blue-Shield of New York |
| S6R | Maine | Anthem Blue-Cross Blue-Shield of Maine |
| S6S | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S6T | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| S6U | Texas | Blue-Cross Blue-Shield of Texas |
| S6V | California | Anthem Blue-Cross |
| S6W | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S6X | California | Anthem Blue-Cross |
| S6Y | Illinois | Blue-Cross Blue-Shield of Illinois |
| S6Z | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S7A | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S7B | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S7C | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S7D | Wisconsin | Anthem Blue-Cross Blue-Shield of Wisconsin |
| S7E | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S7F | California | Anthem Blue-Cross |
| S7G | Virginia | Anthem Blue-Cross Blue-Shield of Virginia |
| S7H | Illinois | Blue-Cross Blue-Shield of Illinois |
| S7I | * | Prefix Unallocated/Not Assigned |
| S7J | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| S7K | New Jersey | Horizon Blue-Cross Blue-Shield of New Jersey |
| S7L | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S7M | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| S7N | * | Prefix Unallocated/Not Assigned |
| S7O | * | Prefix Unallocated/Not Assigned |
| S7P | Illinois | Blue-Cross Blue-Shield of Illinois |
| S7Q | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S7R | California | Anthem Blue-Cross |
| S7S | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S7T | Illinois | Blue-Cross Blue-Shield of Illinois |
| S7U | Texas | Blue-Cross Blue-Shield of Texas |
| S7V | Georgia | Anthem Blue-Cross Blue-Shield of Georgia |
| S7W | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S7X | Illinois | Blue-Cross Blue-Shield of Illinois |
| S7Y | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S7Z | California | Anthem Blue-Cross |
| S8A | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| S8B | Texas | Blue-Cross Blue-Shield of Texas |
| S8C | New York | Empire Blue-Cross Blue-Shield of New York |
| S8D | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8E | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S8F | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8G | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8H | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8I | * | Prefix Unallocated/Not Assigned |
| S8J | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8K | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S8L | Illinois | Blue-Cross Blue-Shield of Illinois |
| S8M | Texas | Blue-Cross Blue-Shield of Texas |
| S8N | Minnesota | Blue-Cross Blue-Shield of Minnesota |
| S8O | * | Prefix Unallocated/Not Assigned |
| S8P | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8Q | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8R | Texas | Blue-Cross Blue-Shield of Texas |
| S8S | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S8T | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S8U | * | Prefix Unallocated/Not Assigned |
| S8V | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8W | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8X | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S8Y | Pennsylvania | Highmark Blue-Cross Blue-Shield of Pennsylvania |
| S8Z | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S9A | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S9B | Alaska | Premera Blue-Cross Blue-Shield of Alaska |
| S9C | Texas | Blue-Cross Blue-Shield of Texas |
| S9D | Indiana | Anthem Blue-Cross Blue-Shield of Indiana |
| S9E | Maryland/District of Columbia/Northern Virginia | Carefirst Blue-Cross Blue-Shield |
| S9F | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S9G | Texas | Blue-Cross Blue-Shield of Texas |
| S9H | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S9I | * | Prefix Unallocated/Not Assigned |
| S9J | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S9K | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S9L | Oregon/Idaho/Utah/Washington | Regence Blue-Cross Blue-Shield |
| S9M | Michigan | Blue-Cross Blue-Shield of Michigan |
| S9N | Texas | Blue-Cross Blue-Shield of Texas |
| S9O | * | Prefix Unallocated/Not Assigned |
| S9P | California | Anthem Blue-Cross |
| S9Q | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S9R | Ohio | Anthem Blue-Cross Blue-Shield of Ohio |
| S9S | Pennsylvania | Independence Blue-Cross of Philadelphia and Southeastern Pennsylvania |
| S9T | Kentucky | Anthem Blue-Cross Blue-Shield of Kentucky |
| S9U | * | Prefix Unallocated/Not Assigned |
| S9V | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S9W | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S9X | Missouri | Anthem Blue-Cross Blue-Shield of Missouri |
| S9Y | * | Prefix Unallocated/Not Assigned |
| S9Z | Connecticut | Anthem Blue-Cross Blue-Shield of Connecticut |
