I have actually been going back to my business classes in order to get a better idea for the feeling of the Noble famalies and their clans which I want to build into my setting. I majored in International Business, specializing in mainly Japanese business and economics.
As many of you are probably not familiar with this world, i'll give you a bit of a summary. Prior to World War II, the Japanese economic world was dominated by the Zaibatsu, vertically integrated family corporations, which locked down and controlled Japanese industry. The Zaibatsu controlled each step of the product manufacturing process, from harvesting raw materials, to selling that product.
However, after the war, the Zaibatsu were forcibly disbanded and the Keiretsu were established. These corporations were not that much different; instead of being vertically integrated, they were horizontally integrated conglomerates. There may have been many companeis in many industries all of which resolved around a corporate bank and shared control of each other. Many of these conglomerates were also based off of the earlier Zaibatsu.
You might be familiar with the company Mitsubishi - one of the biggest and most well known of the Keiretsu. This company has its hands in numerous industries and has the power to loan itself money through its own bank.
If you compare these giant corporations to the family businesses in the rest of the world, you get a very different image in your mind.
The reason that I am writing about this is because I want to create an image of the Noble families of Sigilsval as being these giant Keiretsu spanning multiple industries and having their hands in a lot of different businesses. I hope the summary above is enough to provide an illustration of what I want to accomplish.