What is the ruling regarding an amount deposited into a bank account that has not been claimed by anyone after a full year of its presence in the account?

If the questioner knows that the money exceeds her agreed-upon wage, and she does not know the reason for its addition to her account, this means that it was deposited by mistake. Therefore, it is not permissible for her to own it. She must inform her previous employer and the bank management to correct the error or to explain the reason for the addition.