and if the increase, if any, in redemption price of such obligation described in subdivision (i), (ii), or (iii) of this subparagraph during the taxable year (as described in subparagraph (2) of this paragraph) does not constitute income for such year under the method of accounting used in computing his taxable income, then the taxpayer may, at his election, treat the increase as constituting income for the year in which such increase occurs. If the election is not made and section 1037 (or so much of section 1031 as relates to section 1037) does not apply, the taxpayer shall treat the increase as constituting income for the year in which the obligation is redeemed or disposed of, or finally matures, whichever is earlier. Any such election must be made in the taxpayer's return and may be made for any taxable year. If an election is made with respect to any such obligation described in subdivision (i), (ii), or (iii) of this subparagraph, it shall apply also to all other obligations of the type described in such subdivisions owned by the taxpayer at the beginning of the first taxable year to which the election applies, and to those thereafter acquired by him, and shall be binding for the taxable year for which the return is filed and for all subsequent taxable years, unless the Commissioner permits the taxpayer to change to a different method of reporting income from such obligations. See section 446(e) and paragraph (e) of § 1.446-1 , relating to requirement respecting a change of accounting method. Although the election once made is binding upon the taxpayer, it does not apply to a transferee of the taxpayer.
the increase in redemption price of the series E bond in excess of the amount paid for such series E bond shall be included in the gross income of such taxpayer for the taxable year in which the obligation described in subdivision (i), (ii), or (iii) of this subparagraph is redeemed or disposed of, or finally matures, whichever is earlier, but only to the extent such increase has not previously been includible in the gross income of such taxpayer or any other taxpayer. If such obligation is partially redeemed before final maturity, or partially disposed of by being partially reissued to another owner, such increase in redemption price shall be included in the gross income of such taxpayer for such taxable year on a basis proportional to the total denomination of obligations redeemed or disposed of. The provisions of section 454 (c) and of this subparagraph shall not apply in the case of any taxable year for which the taxpayer's taxable income is computed under an accrual method of accounting or for a taxable year for which an election made by the taxpayer under section 454(a) and paragraph (a) of this section applies. For rules respecting the character of the gain realized upon the disposition or redemption of an obligation described in subdivision (iii) of this subparagraph, see paragraph (b) of § 1.1037-1 .
26 C.F.R. §1.454-1