(d) School infrastructure bond (1) In general For purposes of this section, the term school infrastructure bond means any bond issued as part of an issue if— (A) 100 percent of the available project proceeds of such issue are to be used for the purposes described in section 301 of the Rebuild America’s Schools Act of 2017, (B) the interest on such obligation would (but for this section) be excludable from gross income under section 103, (C) the issue meets the requirements of paragraph (3), and (D) the issuer designates such bond for purposes of this section. (2) Applicable rules For purposes of applying paragraph (1)— (A) for purposes of section 149(b), a school infrastructure bond shall not be treated as federally guaranteed by reason of the credit allowed under subsection (a) or section 6431, (B) for purposes of section 148, the yield on a school infrastructure bond shall be determined without regard to the credit allowed under subsection (a), and (C) a bond shall not be treated as a school infrastructure bond if the issue price has more than a de minimis amount (determined under rules similar to the rules of section 1273(a)(3)) of premium over the stated principal amount of the bond. (3) 6-year expenditure period (A) In general An issue shall be treated as meeting the requirements of this paragraph if, as of the date of issuance, the issuer reasonably expects 100 percent of the available project proceeds to be spent for purposes described in section 301 of the Rebuild America’s Schools Act of 2017 within the 6-year period beginning on such date of issuance. (B) Failure to spend required amount of bond proceeds within 6 years To the extent that less than 100 percent of the available project proceeds of the issue are expended at the close of the period described in subparagraph (A) with respect to such issue, the issuer shall redeem all of the nonqualified bonds within 90 days after the end of such period. For purposes of this paragraph, the amount of the nonqualified bonds required to be redeemed shall be