Is zakat obligatory on money that I deposited with my mother for investment, then she returned it to me after years, knowing that I forgave her for it, but she did not accept?

If the wealth reaches the nisab (definition) (threshold) – 595 grams of silver – its zakat (definition) on shares varies depending on the purpose: if they are for trade, they are appraised at the end of the hawl (lunar year), and their zakat (a quarter of a tenth) is paid from their market value. If they are for retention and benefiting from their yield, then zakat is due on the yield. The hawl for wealth begins from the moment of its ownership. The money taken by the mother is considered a debt, and zakat is paid on it every year if the mother is capable of repayment and the money can be claimed. Otherwise, zakat is paid once upon its retrieval. If the money returns, its zakat becomes due every time a hawl passes over it, as long as it does not fall below the nisab. One must repent from delaying the payment of zakat, as it is obligatory to pay it immediately upon its due date.