Would it be possible to purchase all of your own town shares to prevent any other users from getting the 10% tax?

Unfortunately is not possible

Shares is a good way for people with a deep gold pocket for have additional resource, but first focus on build your town production

But it's possible to buy each other shares, right?
I figured out how to search for town shares if you know user name of player. It's under inventory, financial news, town shares there is search box.
OP, what is your user name in the game?