Wildcard certificate from Comodo.
http://www.positivessl.com/ssl-certificate-positivessl_wildcard.php
SSL Certificates · Wildcard
Get access to data on 12,892,741 websites that are Comodo PositiveSSL Wildcard Customers. We know of 892,279 live websites using Comodo PositiveSSL Wildcard and an additional 12,000,462 sites that used Comodo PositiveSSL Wildcard historically and 422,494 websites in the United States.
Get a list of 12,892,741 websites using Comodo PositiveSSL Wildcard which includes location information, hosting data, contact details, 1,304,457 currently live websites which includes 412,178 domains that redirect to sites in the list. 12,000,462 sites that used this technology previously and 422,494 websites in the United States currently using Comodo PositiveSSL Wildcard.