r = c{(1 + i/b)b/c-1}
In which:
i = The yield based on compounding b times per year expressed as a decimal
r = The equivalent yield based on compounding c times per year expressed as a decimal
b = The number of compounding periods in a year on which i is based (for example, 12, if i is based on monthly compounding)
c = The number of compounding periods in a year on which r is based
OIDshort = IP * (i/k) * f
In which:
OIDshort = The amount of OID allocable to the initial short accrual period
IP = The issue price of the debt instrument
i = The yield to maturity expressed as a decimal
k = The number of accrual periods in a year
f = A fraction whose numerator is the number of days in the initial short accrual period, and whose denominator is the number of days in a full accrual period
26 C.F.R. §1.1272-1