It is a funnier animal than you might think as from the corporate guide pg 31 we have this:
The Z-OG Bank is controlled lock, stock, and barrel by the
Big Ten. The fact that they own equal shares in the bank is one of
the greatest incentives there is to keeping the Big Ten at ten—back
when Cross and Wuxing joined the world’s most exclusive club,
the members of the then-Big Eight all lost a little bit of influence
in the Z-OG Bank, since they had to share it with two other
shareholders. So while the Big Ten coordinate together to promote
their efforts through the Corporate Court and the Z-OG Bank,
none of them ever forget that they’d have even more power if one
of their compatriots fell by the wayside.
The Z-OG Bank is organized to keep everyone involved and
a little bit hungry. There are only nine seats on Z-OGB’s board
of directors (the holders of those seats are collectively known as
the “Gnomes”); each director represents one mega, and each of
them serves a nine-year term. That means that someone’s term
ends every year. When that happens, the corp that person was
representing takes a year off from board membership, rejoining
at the beginning of the following year. Currently, Ares is suffering
through a year off of the board; next year, Wuxing takes the trip
to purgatory. Corporations live in continual dread of the year off,
and they are making plans on how to endure it from the moment
their nine-year term starts. Then they spend the year off frantically
making plans for the next nine-year period so their board member
can hit the ground running.
The board is selected by the Big Ten CEOs themselves.
During their time on the board, they collect two salaries; one from
their parent corp, one from the Z-OG Bank. In theory, this makes
directors continually remember to balance their loyalties between
their corp and the bank. In practice, this makes a position on the
board even more coveted than it would otherwise be, meaning
those who make it to the top are cutthroat survivors. On the plus
side, the high level of compensation makes the directors fairly
resistant to bribery, which is important to the CEOs.
In many ways it is a modern verison of the kieretsu model albeit in a bit looser organization, interlinking the corps and the Z-OG.
So can the common Joe (no pun intended CJ) on the street buy stock in Z-OG?
I don't think so... he is part of the system everytime he uses nuyen to purchase things as well as his account might be with Z-OG or other banks, but not as a shareholder since Z-OG does not need to have anyone outside of the corps as shareholders and they are also virtually printing money, so they are both Bank and Mint rolled into one.
Plus do not forget Z-OG actually buys and sells other companies stocks as well, like the time Miles Lanier sold out his shares in Renraku to Z-OG at below market price just to mess with the big red R, so it has considerable powers by itself.
But I could be wrong and maybe Nath can shed some light on this as he does have a better grasp than I for all things financial in-game.
Edit: dug a bit further back and in Corporate download pg 23 they mention how Global Financial Services, the forerunner of Z-OG, was basically handling the majority of money transactions by the Big Seven and how precarious this was if this were to fall apart so they convinced the corps to basically hand it all over to the CC so as to ensure a balance to inter-megacorp power and to prop up the CC authority and this would become the Z-OG we know and love today. No mention is made of shares/stocks during this transition beyond it all being handed over to the CC, so it could be there are type B sort of stocks but they never seem to be mentioned anywhere.
