We base current redemption values (CRV) for book-entry Series I savings bonds on the definitive savings bonds CRV. To calculate the book-entry values, we use the CRV for the $100 denomination Series I savings bonds and calculate a CRV prorated to the book-entry par investment amount for the corresponding issue and redemption dates. Calculated book-entry CRV will be rounded to the nearest one cent. The formula is as follows (Examples of the calculation are given in appendix A to part 359.):
Example: Calculated value of $25.044 rounds to $25.04; calculated value of $25.045 rounds to $25.05.
[Book-entry par investment ÷ 100] * [CRV value for $100 bond].
31 C.F.R. §359.55