How is the zakat on a company's capital calculated and when is it due, given that the company was established in Rabi' al-Awwal, the due date for one's personal zakat on wealth is in Ramadan, and each partner has a different due date for their personal zakat?

There is no zakat (definition) on someone whose share in a company does not individually reach the nisab (definition), or when combined with other money or trade goods they own, because the commingling of funds, according to the majority of jurists, does not affect zakat except for livestock. Partners must maintain regular accounts to determine profits and ascertain the amount of each partner's capital and profit at the end of the year, in order to promptly pay zakat. As for money taken from the bank, if it is for a permissible transaction, it is lawful; if it is for an interest-based transaction, it is unlawful and no zakat is due on it. It must be disposed of by spending it on public welfare.