How should zakaah on wealth belonging to orphans be paid?
Question

                I have some orphans under my care. I bought some shares in their name using my own capital, and when I sell the shares, I take back my capital and the profit remains in their account. Please note that some wealth has accumulated from these earnings for them, and I invest some of these earnings and some of that remains in their account, and one year has passed for some of the earnings. 

My question is: How should zakaah be paid in this case, because they are minors and any zakaah is to be paid from their monthly income? Please note that their monthly income covers their needs.
Praise be to Allah.
      Everyone who possesses wealth that reaches the minimum 
      threshold (nisaab) and one year has passed since he acquired it, is 
      obliged to pay zakaah on it, whether he is old or young, of sound mind or 
      otherwise. 

    No differentiation is made between orphans and others in this 
    case, because zakaah is what is due from wealth, as Allaah says 
    (interpretation of the meaning):

    “Take Sadaqah (alms) from their wealth in order to purify 
    them and sanctify them with it”

    [al-Tawbah 9:103]. 

    In Fataawa al-Lajnah al-Daa’imah (14/293) it says: It 
    is obligatory for the guardian (wali) to pay the obligatory zakaah on the 
    wealth of minors if it reaches the nisaab and one year has passed since it 
    was acquired. End quote. 

    This has been discussed in detail in the answer to question 
    no. 75307. 

    Based on that: 

    1.If the wealth of each of these 
    orphans has reached the nisaab as defined in sharee‘ah (the value of 595 
    grams of silver), then you have to pay zakaah on his behalf.

    2.With regard to the profits that 
    you put in their account, if it came from your capital then it is a gift 
    from you to them, and it comes under the same heading as wealth acquired 
    during the year. So you should work out a separate year for that, starting 
    from the date you gave it to them.

    see the answer to question no.
    93414.

    3.With regard to the profits that 
    come from their own capital, they should not work out a separate year for 
    that; rather the year for them starts from the date the capital was acquired 
    and zakaah should be paid on (the profits) at the same time.

    One of the duties of the wasiy (guardian) is to take care of 
    orphans placed under his care, look after them, protect their wealth and 
    invest it according to what is in their best interests according to 
    sharee‘ah. There is no doubt that what you are doing, using your money for 
    trading in shares and putting the profits in their account, is a good and 
    righteous deed for which you will be rewarded. 

    And Allah knows best.