Is Zakat obligatory on the entire saved amount, or only on the portion that has been held for a full year?

In summary, the newly acquired wealth (mal mustafad) must have zakat paid on it upon the completion of its own hawl (one lunar year) if it is not an increment of existing capital. This is the view of the majority of scholars. However, if the newly acquired wealth is an increment of existing capital, then it is added to the original capital and its zakat is paid along with it, by consensus. It is permissible to pay the zakat on all wealth in advance when the hawl of the original capital is completed.