The Dwarven Merchants Guild is, without question, the most powerful surface dwarf institution. It has become what the Assembly is to the people of Orzammar: a prestigious club that everyone wants to belong to and the surest means to obtain power and fortune. The guild's leaders can always trace their lineage back to Noble or Merchant Caste houses in Orzammar. The guild regulates trade between the dwarven city and the surface and quietly controls the entire economy of Orzammar, though the ruling king or Assembly would never admit it.
The guild is heavily conservative, but has started to get more of the ascendants—especially banking families—into its membership, which has caused no small amount of infighting in the guild.
—From The Dowager's Field Guide to Good Society by Lady Alcyone