I say, and with God's help: Zakat is obligatory on it; because the will is considered an optional cause for ownership, and it is accompanied by the intention of trade at the time of the occurrence of the cause of ownership, which necessitates zakat. This is unlike someone who intends to trade after the occurrence of the optional cause of ownership, for zakat is not obligatory on him unless he sells it; because the intention is only considered if it exists at the time of the occurrence of the cause of ownership. And God knows best.