A Wildcard Certificate is issued to a domain and all of its subdomains for encrypting traffic. For example, if paypal had a wildcard certificate that same certificate would work for paypal.com as well as contact.paypal.com or support.paypal.com or any other subdomains they might have. With wildcard certificate's companies do not need to purchase additional certificates for subdomains. However, paypal does not have a wildcard certificate because it is not possible to obtain a wildcard certificate that is also an EV certificate.