They are. See section (g)(4) of: https://www.law.cornell.edu/uscode/text/26/402 https://www.law.cornell.edu/uscode/text/26/402 Everything, including the round

They are. See section (g)(4) of: https://www.law.cornell.edu/uscode/text/26/402 https://www.law.cornell.edu/uscode/text/26/402 Everything, including the rounding to a multiple of $500, is specified in the law.