All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.

Zakat is one of the pillars of Islam, an obligatory act of worship, and one of the most significant acts of devotion. It is closely related to prayer, as mentioned in the Quran, "Establish prayer and give zakat." {Al-Baqarah, 43}. Zakat is obligatory on wealth when it reaches the prescribed Nisab (Minimum amount liable for Zakat) and one full lunar year passes over possessing it, because it has met the conditions for zakat. Therefore, it should be paid every lunar year.

Zakat is obligatory on every owned wealth, whether the person is aware that he owns it or not, as in the case described in the above question. This person is required to pay Zakat for the past years, and their lack of awareness of the ownership of that wealth does not exempt them from this obligation. This is because Zakat is both a right tied to the wealth and their ownership of that wealth continued over the past years.

Imam al-Khatib al-Shirbini, may Allah have mercy on him, stated, "Zakat is obligatory on property taken by force if the owner cannot reclaim it, just like stolen property. However, Imam al-Nawawi didn`t mention the ruling of Zakah on stolen property although it was mentioned in the book "Al-Muharrar." This is because the definition of the property taken by force applies to stolen property……... Payment of Zakat is not required until the rightful owner reclaims that property, stolen or taken by force. When the owner reclaims it, Zakat is due for the previous years. If it only reaches the Nisab and there is nothing of the same kind available to compensate for what is required, Zakat is not due for what exceeds the first year." [Moghni al-Muhtaj, Vol.2, Page 123].

The scholars of the Maliki school of thought are of the opinion that there is no Zakat on inherited wealth for the past years before it was received. When it is received, it starts a new Zakat cycle. As mentioned in [Al-Sharh al-Kabeer by Sheikh Al-Dardeer and the commentary by Al-Dasuqi, Vol.1, Page 457] from the works of the Maliki scholars: "There is no Zakat on a specific property that has been inherited and remained for several years if no one was aware of it... The implication of the Maliki school's view is that there is no Zakat on that property until it is received. When it is received, it initiates a new Zakat cycle, and there is no Zakat on the previous years."

In conclusion, according to the Shafi'i scholars, the heirs are required to pay Zakat on stocks, wealth, and the associated profits for the past years when they are received. This is more prudent and clears them from liability before Almighty Allah. Those who follow the Maliki view, which states that there is no Zakat on the past years before receiving the wealth, and that it starts a new Zakat cycle upon reception, may do so with the hope of acceptance from Allah. However, it should be noted that the profits generated during the entire period should be given in charity if the bank is based on Riba (Usury/interest). It is also important to get rid of these stocks. On the other hand, if the bank operates in accordance with Islamic principles, there is no problem in holding the profits, but Zakat should be paid on them as previously explained. And Allah the Almighty knows best.