Is Zakat obligatory on pension salaries that are paid into an investment fund, knowing that the money cannot be withdrawn until after retirement?

Zakat (definition) is not obligatory on money saved in an employee's pension fund because his ownership of it is not complete, and he cannot dispose of it before retirement. Zakat is imposed on these funds only after they are received, and they are added to the rest of the zakatable wealth and zakat is paid on them as newly acquired wealth.