; multiplied by (B) the cost-of-living adjustment determined under section 1(f)(3) of the Internal Revenue Code of 1986, determined by substituting the calendar year preceding the year described in subsection (f)(1) for calendar year 2016 in subparagraph (A)(ii) thereof. (2) Rounding If any amount adjusted under paragraph (1) is not a multiple of $500, such amount shall be rounded to the next lowest multiple of $500. 5. Regulation of tax return preparers (a) In general Subsection (a) of section 330 of title 31, United States Code, is amended— (1) by striking paragraph (1) and inserting the following: (1) regulate— (A) the practice of representatives of persons before the Department of the Treasury; and (B) the practice of tax return preparers; and ; and (2) in paragraph (2)— (A) by inserting or a tax return preparer to prepare tax returns after practice ; (B) by inserting or tax return preparer before demonstrate ; and (C) by inserting or in preparing their tax returns, claims for refund, or documents in connection with tax returns or claims for refund after cases in subparagraph (D). (b) Authority To sanction regulated tax return preparers Subsection (c) of section 330 of title 31, United States Code, is amended— (1) by striking before the Department ; (2) by inserting or tax return preparer after representative each place it appears; and (3) in paragraph (4), by striking misleads or threatens and all that follows and inserting misleads or threatens— (A) any person being represented or any prospective person being represented