They sell journalism under the NBC brand. Is this a serious question? If CNBC was issuing paid advertisement like that it would be a much, much bigger story than a spike in a small cap retail stock.
Only a small segment during the 247 news station day is actually designated as news. Everything else is news entertainment which has different regulations.
I still don't see what this has to do with the point above, which is that a promoted tweet from CNBC for one of their segments is clearly not a paid advertisement by the guest in the segment.
You don't think it is relevant in a discussion about deceptive paid primetime television marketing, that the company in question has the highest documented rate of deceptive paid primetime marketing?
OK, you're just misunderstanding. "Primetime Television" is a marketing term that refers to the traditional TV network programming scheduled between 8-10pm. This is where they put the sitcoms and dramas and reality shows. And "Product Placement" refers not to advertising per se, but paid placement of retail products (e.g. cars, sodas, whatever) into the scenes in the fiction, or to appear as prizes, etc...
It doesn't refer to news programming or other journalism, you just got confused. And I'll say it again: if NBC News, or any other major news media organization, ever got caught teasing a segment because of third party payment, it would be a much, much (seriously: much) bigger story than this minor nonsense about GameStop. They simply do not do what you are alleging, period.
https://ufdc.ufl.edu/UF00101603/00001