Is it permissible to give Zakat al-Mal (obligatory charity) to Islamic organizations, such as Islamic Relief, which allocate 20% of it for administrative purposes?

It is permissible to pay Zakat to organizations and institutions designated by a government that permits the payment of Zakat to them. It is also permissible for a portion of it to be spent on administrative affairs, as they are considered "those employed to collect them" (al-ʿamilīna ʿalayhā). As for independent organizations and institutions, they are not permitted to spend Zakat funds on administrative expenses, because they are charitable entities acting on behalf of the Zakat payer to deliver Zakat to its rightful recipients, and the term "those employed to collect them" does not apply to them.