Nogizaka46 46 46llc refers to Nogizaka46 Contract Association. Responsible for Nogizaka46's public performance (this is just my guess)
Sony refers to Sony music. This is the agency of Nogizaka46 and Danban 46.
AKS is the operating company (that is, the brokerage company) of 48group. Except NMB48, most graduate students and full members of other groups belong to this company.