In response to this issue, Dr. Monzer Kahf, a prominent economist and counselor, states:
“The terms amwal zahirah (visible wealth) and amwal batinah (hidden wealth) are fiqhi terms created by scholars while discussing the procedures of Zakah collection. These two terms did not come in the Qur’an nor in the Sunnah of our beloved Prophet (peace and blessings be upon him).
Visible wealth is made of those apparent or visible items of property that the collector can normally see, count or estimate, and consequently can be sure to collect the Zakah exactly and accurately. At the time of the great jurists of Islam, that is, the second to fourth centuries of Hijrah, these items included livestock and agricultural products.
Hidden wealth is made of those items of property that are normally not apparent or visible; they are subject to Zakah but the collector does not normally see them and has no means to know about them except by disclosure of the owner. At that time these items included money, inventory of goods for trade, debts on others and jewelry. These items are normally under the hand of the owner and are not exposed to the public and the collector without willful exposure by the owner.
It is noticed from the definition that the way items of property are handled influences this classification.
That is why one finds that an item is sometimes shifted from one category to the other on the basis of its way of handling. For instance, since day one, classical scholars argued that trade inventory that is shipped by caravans that pass by the collection points on the highways must be included in the visible category because collectors have accessibility to see and count it.
By the same token, bank accounts may be classified under the visible category if the law requires disclosure by the depository bank, although they are either money or debts, while farm cattle may not be visible because a collector doesn’t have accessibility to count them and has to depend on owner disclosure.”