Is zakat obligatory on an amount owed to a retirement fund and deposited in an Islamic bank, knowing that it is not currently required to be paid except upon termination of service?

Zakat is obligatory on the aforementioned amount if it reaches the nisab (minimum threshold) and a hawl (full lunar year) passes over it, due to the Prophet's (peace be upon him) saying: "There is no zakat on wealth until a year passes over it."