Fiqh-us-Sunnah Volume 3, Zakaat and Fasting, Fiqh 3.050.

The amount payable on rikdz is one-fifth, regardless of a nisab, according to Abu Hanifah, Ahmad, and one of the two correct reports of Malik and ash-Shaf’i. As for the completion of a year (haws), all scholars agree that it has not been stipulated as a condition.