| K2A | Blue Cross Blue Shield of Texas |
| K2B | Blue Cross Blue Shield of Texas |
| K2C | Regence Blue Cross Blue Shield |
| K2D | Blue Cross Blue Shield of Illinois |
| K2E | Anthem Blue Cross of California |
| K2F | Blue Cross Blue Shield of Illinois |
| K2G | Blue Cross Blue Shield of Oklahoma |
| K2H | Blue Cross Blue Shield of Western New York |
| K2I | Unassigned Prefix |
| K2J | Highmark Blue Cross Blue Shield |
| K2K | Highmark Blue Cross Blue Shield |
| K2L | Highmark Blue Cross Blue Shield |
| K2M | Horizon Blue Cross Blue Shield |
| K2N | Blue Cross Blue Shield of Vermont |
| K2O | Unassigned Prefix |
| K2P | Horizon Blue Cross Blue Shield |
| K2Q | Unassigned Prefix |
| K2R | Highmark Blue Cross Blue Shield |
| K2S | Premera Blue Cross |
| K2T | Blue Cross Blue Shield of Minnesota |
| K2U | Highmark Blue Cross Blue Shield |
| K2V | Highmark Blue Cross Blue Shield |
| K2W | Anthem Blue Cross Blue Shield of Kentucky |
| K2X | Blue Cross Blue Shield of Illinois |
| K2Y | Anthem Blue Cross Blue Shield of Indiana |
| K2Z | Anthem Blue Cross Blue Shield of Kentucky |
| K3A | Anthem Blue Cross of California |
| K3B | Empire Blue Cross Blue Shield |
| K3C | Anthem Blue Cross Blue Shield of Virginia |
| K3D | Unassigned Prefix |
| K3E | Unassigned Prefix |
| K3F | Anthem Blue Cross Blue Shield of Georgia |
| K3G | Regence Blue Cross Blue Shield |
| K3H | Highmark Blue Shield |
| K3I | Unassigned Prefix |
| K3J | Unassigned Prefix |
| K3K | Unassigned Prefix |
| K3L | Highmark Blue Shield |
| K3M | Anthem Blue Cross of California |
| K3N | Blue Cross Blue Shield of Texas |
| K3O | Unassigned Prefix |
| K3P | Anthem Blue Cross Blue Shield of Virginia |
| K3Q | Anthem Blue Cross Blue Shield of Georgia |
| K3R | Highmark Blue Shield |
| K3S | Premera Blue Cross |
| K3T | Anthem Blue Cross of California |
| K3U | Blue Cross Blue Shield of Illinois |
| K3V | Regence Blue Cross Blue Shield |
| K3W | Unassigned Prefix |
| K3X | Unassigned Prefix |
| K3Y | Unassigned Prefix |
| K3Z | Anthem Blue Cross Blue Shield of Georgia |
| K4A | Empire Blue Cross Blue Shield |
| K4B | Anthem Blue Cross Blue Shield of Indiana |
| K4C | Blue Cross Blue Shield of Michigan |
| K4D | Anthem Blue Cross Blue Shield of Ohio |
| K4E | Unassigned Prefix |
| K4F | Regence Blue Cross Blue Shield |
| K4G | Carefirst Blue Cross Blue Shield |
| K4H | Unassigned Prefix |
| K4I | Unassigned Prefix |
| K4J | Unassigned Prefix |
| K4K | Unassigned Prefix |
| K4L | Anthem Blue Cross Blue Shield of Ohio |
| K4M | Empire Blue Cross Blue Shield |
| K4N | Blue Cross of Massachusetts |
| K4O | Unassigned Prefix |
| K4P | Unassigned Prefix |
| K4Q | Unassigned Prefix |
| K4R | Empire Blue Cross Blue Shield |
| K4S | Blue Cross of Massachusetts |
| K4T | Carefirst Blue Cross Blue Shield |
| K4U | Blue Cross Blue Shield of Illinois |
| K4V | Blue Cross Blue Shield of Texas |
| K4W | Unassigned Prefix |
| K4X | Unassigned Prefix |
| K4Y | Unassigned Prefix |
| K4Z | Anthem Blue Cross Blue Shield of Indiana |
| K5A | Anthem Blue Cross of California |
| K5B | Anthem Blue Cross Blue Shield of Ohio |
| K5C | Anthem Blue Cross Blue Shield of Indiana |
| K5D | Blue Cross Blue Shield of Illinois |
| K5E | Unassigned Prefix |
| K5F | Anthem Blue Cross Blue Shield of Indiana |
| K5G | Unassigned Prefix |
| K5H | Unassigned Prefix |
| K5I | Unassigned Prefix |
| K5J | Unassigned Prefix |
| K5K | Unassigned Prefix |
| K5L | Unassigned Prefix |
| K5M | Unassigned Prefix |
| K5N | Anthem Blue Cross Blue Shield of Indiana |
| K5O | Unassigned Prefix |
| K5P | Blue Cross Blue Shield of Illinois |
| K5Q | Unassigned Prefix |
| K5R | Unassigned Prefix |
| K5S | Unassigned Prefix |
| K5T | Unassigned Prefix |
| K5U | Unassigned Prefix |
| K5V | Blue Cross Blue Shield of Texas |
| K5W | Unassigned Prefix |
| K5X | Unassigned Prefix |
| K5Y | Anthem Blue Cross Blue Shield of Kentucky |
| K5Z | Unassigned Prefix |
| K6A | Empire Blue Cross Blue Shield |
| K6B | Anthem Blue Cross Blue Shield of Georgia |
| K6C | Empire Blue Cross Blue Shield |
| K6D | Unassigned Prefix |
| K6E | Unassigned Prefix |
| K6F | Unassigned Prefix |
| K6G | Unassigned Prefix |
| K6H | Unassigned Prefix |
| K6I | Unassigned Prefix |
| K6J | Unassigned Prefix |
| K6K | Unassigned Prefix |
| K6L | Unassigned Prefix |
| K6M | Anthem Blue Cross Blue Shield of Virginia |
| K6N | Unassigned Prefix |
| K6O | Unassigned Prefix |
| K6P | Unassigned Prefix |
| K6Q | Unassigned Prefix |
| K6R | Unassigned Prefix |
| K6S | Unassigned Prefix |
| K6T | Unassigned Prefix |
| K6U | Unassigned Prefix |
| K6V | Unassigned Prefix |
| K6W | Unassigned Prefix |
| K6X | Unassigned Prefix |
| K6Y | Unassigned Prefix |
| K6Z | Unassigned Prefix |
| K7A | Anthem Blue Cross Blue Shield of Indiana |
| K7B | Anthem Blue Cross Blue Shield of Indiana |
| K7C | Anthem Blue Cross Blue Shield of Indiana |
| K7D | Anthem Blue Cross Blue Shield of Indiana |
| K7E | Anthem Blue Cross Blue Shield of Indiana |
| K7F | Anthem Blue Cross Blue Shield of Indiana |
| K7G | Unassigned Prefix |
| K7H | Unassigned Prefix |
| K7I | Unassigned Prefix |
| K7J | Unassigned Prefix |
| K7K | Unassigned Prefix |
| K7L | Unassigned Prefix |
| K7M | Anthem Blue Cross Blue Shield of Ohio |
| K7N | Anthem Blue Cross Blue Shield of Indiana |
| K7O | Unassigned Prefix |
| K7P | Unassigned Prefix |
| K7Q | Unassigned Prefix |
| K7R | Unassigned Prefix |
| K7S | Regence Blue Cross Blue Shield |
| K7T | Unassigned Prefix |
| K7U | Unassigned Prefix |
| K7V | Unassigned Prefix |
| K7W | Unassigned Prefix |
| K7X | Blue Cross Blue Shield of Texas |
| K7Y | Unassigned Prefix |
| K7Z | Unassigned Prefix |
| K8A | Anthem Blue Cross Blue Shield of Colorado |
| K8B | Unassigned Prefix |
| K8C | Anthem Blue Cross of California |
| K8D | Unassigned Prefix |
| K8E | Unassigned Prefix |
| K8F | Unassigned Prefix |
| K8G | Unassigned Prefix |
| K8H | Unassigned Prefix |
| K8I | Unassigned Prefix |
| K8J | Unassigned Prefix |
| K8K | Unassigned Prefix |
| K8L | Unassigned Prefix |
| K8M | Anthem Blue Cross of California |
| K8N | Unassigned Prefix |
| K8O | Unassigned Prefix |
| K8P | Blue Cross Blue Shield of Texas |
| K8Q | Unassigned Prefix |
| K8R | Unassigned Prefix |
| K8S | Unassigned Prefix |
| K8T | Unassigned Prefix |
| K8U | Unassigned Prefix |
| K8V | Unassigned Prefix |
| K8W | Unassigned Prefix |
| K8X | Unassigned Prefix |
| K8Y | Blue Cross Blue Shield of Arizona |
| K8Z | Blue Cross Blue Shield of Arizona |
| K9A | Anthem Blue Cross Blue Shield of Georgia |
| K9B | Anthem Blue Cross Blue Shield of Georgia |
| K9C | Anthem Blue Cross Blue Shield of Georgia |
| K9D | Anthem Blue Cross Blue Shield of Indiana |
| K9E | Unassigned Prefix |
| K9F | Unassigned Prefix |
| K9G | Anthem Blue Cross Blue Shield of Georgia |
| K9H | Unassigned Prefix |
| K9I | Unassigned Prefix |
| K9J | Unassigned Prefix |
| K9K | Anthem Blue Cross Blue Shield of Indiana |
| K9L | Unassigned Prefix |
| K9M | Anthem Blue Cross Blue Shield of Indiana |
| K9N | Anthem Blue Cross Blue Shield of Georgia |
| K9O | Unassigned Prefix |
| K9P | Unassigned Prefix |
| K9Q | Unassigned Prefix |
| K9R | Unassigned Prefix |
| K9S | Unassigned Prefix |
| K9T | Unassigned Prefix |
| K9U | Unassigned Prefix |
| K9V | Unassigned Prefix |
| K9W | Anthem Blue Cross Blue Shield of Indiana |
| K9X | Unassigned Prefix |
| K9Y | Regence Blue Cross Blue Shield |
| K9Z | Unassigned Prefix |
