I say, and with Allah's success: It is permissible to advance zakat for a year or more after owning the nisab; one can pay it at any time without being restricted to a specific date, provided that one is only the owner of the nisab. Thus, it is valid to present it before a year has passed on the nisab, for the reason is the growing wealth; wealth is the essence, and growth is a description of it. Therefore, it is permissible to perform it after the existence of its essence. And because growing wealth is the reason for the obligation of zakat, and the year is a condition for the obligation of performance, if the reason exists, the performance is valid even if it has not become obligatory. If the nisab is present, the performance is valid before the year; as Ali (may Allah be pleased with him) said: 'Indeed, Al-Abbas (may Allah be pleased with him) asked the Messenger of Allah (peace be upon him) about advancing charity before it is due, and he permitted that.' This is found in Sunan Al-Darimi 1: 470, Al-Muntaka 1: 98, Sahih Ibn Khuzaymah 4: 48, Al-Mustadrak 3: 375, as mentioned in Sharh Al-Waqayah, p. 217, Umdat Al-Riayah, 1: 284, and Tabyin Al-Haqaiq, 1: 275-276, and Allah knows best.