They are owned by the same group of individuals, but they don't want us to know and it's not just 1xbet and 1xbit, there are so many more. if you want to prove this just head over to 1xbet chat and ask them if they are related to 1xbit they will just end the chat without telling you a direct answer.
Without being told, I already knew that 1xbet and 1xbit are heavily related or connected. It is just a common sense that made me conclude firmly that they are owned by same individuals. See my reasons;
If company A has similar domain name with company B, company A doesn't scam but company be does. If they aren't related, company A would make public notice disassociating itself from company B, it could also take legal action against company B.
But in the case of 1xbet and 1xbit, both seems unconcerned and never had the strong will to explain their distinction without any trace of doubt.
What I have to say is that the parent company decided to use one brand name for fiat casino and the other for online. While they are very shady to a high extent with the cryptocurrency version 1xbit, they seems to be doing nice with 1xbet the fiat version.
Then, if you scam with one branch of you and become a saint in the other, you can't be trusted.
The similarity they share apart from name is their ability to invest much in promotions. So, you can try as much as possible to avoid both.