It's because like NBC, They don't have one..
check this article from Forbes….
https:// www.forbes.com/sites/markjoyella/2017/10/11/trump-threatens-to-challenge-nbcs-license-over-fake-news/#403d74d6a128
https://www.forbes.com/sites/markjoyella/2017/10/11/trump-threatens-to-challenge-nbcs-license-over-fake-news/#403d74d6a128
In brief summary of what I think is the point…
"We license only individual broadcast stations. We do not license TV or radio networks (such as CBS, NBC, ABC or Fox) or other organizations with which stations have relationships (such as PBS or NPR), except to the extent that those entities may also be station licensees. We also do not regulate information provided over the Internet, nor do we intervene in private disputes involving broadcast stations or their licensees. Instead, we usually defer to the parties, courts, or other agencies to resolve such disputes."