The .981 change log says, among other things:
Fixed the Market and Merchantcross Bazzar (so they are now buildable in towns)
Please check the Tax Office to see if it has the same problem. I have a level 3 town and have the Cooperation tech for Tax Office, but it has not appeared in the build list. I also have the Economics tech, which enables the Treasury Vault, but it is not buildable either, I presume because it requires the Tax Office first.
I can supply a saved game, if needed.
