Not sure where you're getting that info from. 1D Media Ltd was registered in December 2010. Each of the lads were directors (in layman's terms, the managers) and owned 20% of the business each. In 2016, all five resigned as directors and new directors were brought in. Harry, Louis, Liam and Niall then became solely persons with significant control (i.e. the owners) of 1D Media Ltd. and now own 25% of the business each. Liam's involvement ceased on the date of his death. From what I can see, this is the only 1D-owned business where Zayn's shares were bought/given back; all the others he still has, or had if they've since shut down, a 20% share in.
To answer
@MammaTubbs related question: Liam's shares in the 1D-owned businesses, copyrights and trademarks now go to Bear. Anything related to these that would have required Liam's consent would now require Bear's.
According to the records on Companies House, Liam signed the majority of the accounting paperwork for a lot of the 1D-owned businesses, which makes it even weirder that he didn't have a will. I guess they all could have been given the info and Liam was volunteered by the others to sign it, in his role as "Daddy" of the group, and he didn't really know what he was signing; but I find that hard to believe. Especially considering he signed some of them after 1D had split. It's very strange.