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**HP 30b programs for interest rate conversions with negative or fractional periods per year**

*Posted by gene wright on 3 May 2011, 2:30 p.m.*

These programs allow the use of negative values for "Periods per year" when converting interest rates. They also allow the use of fractional periods per year. End of period compounding assumed.

First program: Computing the effective rate. Inputs: Nominal rate, =, number of periods.

/ Ans ) Swap 1 + ) Swap Y^X 1 - Shift+Stop

When run from the program catalog, key 0.1224 = 2 +/- = =

Result shown is 0.1346

2nd program: Effective rate to nominal rate. Inputs: Effective rate, =, number of periods.

= = shift+UP 1 + ) Swap 1/x Y^X 1 - * Shift+STOP

Inputs: 0.1346 = 2 +/- = =

Outputs 0.1224

Inputs: 0.1346 = 360 = 210 / =

Outputs: 0.1310