Is Zakat obligatory on shares if the value of their Zakat is equal to three-quarters of their annual profits?

Zakat is obligatory on the value of shares, in addition to their profits, if their value reaches the nisab and a year has passed over them. One-quarter of one-tenth (2.5%) of the total is then to be given, provided that the profits are lawful. However, if the profits are usurious, they must be disposed of by spending them on charitable causes, and Zakat is then to be paid only on the value of the shares.