The De Minimis Rule for nonsigning preparers says that a portion of the return will not be considered substantial if the item in question or claim for refund involves related amounts that are: Reported on one form or less completed by the non-signing preparer. Less than $2,500; or less than $100,000 and also less than 5% of the gross income as shown on the return or claim for refund. Less than $5,000; or less than $200,000 and also less than 10% of the gross income as shown on the return or claim for refund. Less than $10,000; or less than $400,000 and also less than 20% of the gross income as shown on the return or claim for refund.