Excerpts from A Question of Nobility by Marcus Bloch, Fated scholar:
...which leads us to the question "Where do the moneyed nobility of Sigil come from?" Clearly they do not have any social privileges beyond that which their money can purchase, yet they still sequester themselves like arrogant and foolish Primes in the Lady's Ward or the Clerks. They might insist that you call them "Sir" or "Ma'am" or some such appellation and a good many of them are human. So where oh where do these people come from?
To understand that, we have to examine the planar economy just a fraction. In the Planes the most lucrative positions are those which do no work: Joint-stock investors and merchants. We also need to realize that a great deal of wealth is generated from the Prime, where true nobility DOES exist and they leech off of the acquired wealth of the masses. So, the greatest transmission of wealth occurs when goods are purchased for a low price on one plane or geographical locale and sold for a higher price somewhere else. These passive actors, purveyors, leech off of the hard work of others in order to provide relevant services. Never pay for what you can acquire yourself is the first lesson learned! Secondly, because of the lucrative nature of trade the merchants can afford to hire other go betweens who will be paid only a fraction of the profits, thus amassing wealth into mercantile hands.
This dead money ceases to circulate as the merchant rapidly acquires more than he can spend on himself or on his growing business. In the ideal case the merchant then uses his wealth to buy himself a great palace somewhere in the Spires in the Lady's. This would seem the natural order of things at first: a man or woman, getting by on the strength of their cunning and some hard work. Yet once a critical sum is amassed the merchant may then invest in joint-stock ventures, owning portions of the companies of others or in land, owning a tithing of rents from some meager tenants in the Lower Ward. In this way, the merchant ceases to work. Instead, his money works for him. When he dies, his children inherit his fortune and the rents he is guaranteed to collect and the whole lot. This is the basis of the moneyed gentry.
There is a second, lesser source of moneyed gentry, and that is an influx of wealthy Primes (whether mages or some other type with easy access to great amounts of jink stashed in their home spheres) though this accounts for quite few of the so-called elite classes.
It is for this reason that I propose an estate tax be passed in the Hall of Speakers at once, to reduce the jink-intertia that plagues the upper classes of Sigil!