Musannaf Ibn Abi Shaybah

Dawud narrates that Imam Shabi did not consider anything obligatory on more than two hundred dirhams until it reached forty.

Hasan narrates that Hazrat Umar wrote to Hazrat Abu Musa Ash'ari: If it exceeds two hundred dirhams, then for every forty dirhams, one dirham (as zakat) is due.

Hasan says that nothing will be due on more than two hundred dirhams until they reach forty.

Hazrat Mak'hool says that nothing will be due on more than two hundred dirhams until the excess reaches forty.

Hazrat Ata says that when the amount exceeds two hundred and reaches forty dirhams, then six dirhams (zakat) are due on it. Then nothing is due until the amount reaches two hundred and eighty, upon which seven dirhams (zakat) are due. Then continue calculating in this manner.