Distributing holdings

If someone is distributing part of their holdings and they aren’t on outstanding shares or the float, where are they? I thought outstanding shares were all shares.

Trying to understand the Graftech situation.

So can a company be partly private and public?

In theory 50pc of the company could go IPO and which would be the float and then at some point a private shareholder who owns the remainder could put the other 50pc on for 100pc float?