Posted by Mike McNelley on Mon, Jun 18, 2012 @ 10:03 AM
Question: What is the calculation for monthly payment amounts on fixed interest rate annuities where the interest rate is an effective annual interest rate?
Because you lose the effect of annual compounding, the formula is a little more complicated when calculating the amount of interest actually being paid out.
The interest calculation is *:
((1+(Interest Rate/100)) ^ (#of days of interest/#of days in fiscal year)) x Principal - Principal
For example, for a $90,000 principal, 3.40% annual rate, 365-day fiscal year, ‘monthly’ interest distribution from the annuity:
For 30 days in the payment period:
((1+(3.40/100))^(30/365)) x $90,000 - $90,000
(1.0340^.08219) x $90,000 - $90,000
1.0027518 x $90,000 - $90,000 = $90,247.66 - $90,000 = $247.66
For 31 days in the payment period:
((1+(3.40/100))^(31/365)) x $90,000 - $90,000
(1.0340^.08493) x $90,000 - $90,000
1.0028437 x $90,000 - $90,000 = $90,255.93 - $90,000 = $255.93
For 28 days in the payment period:
((1+(3.40/100))^(28/365)) x $90,000 - $90,000
(1.0340^.07671) x $90,000 - $90,000
1.0025681 x $90,000 - $90,000 = $90,231.13 - $90,000 = $231.13
Values can be determined using a calculator with a ‘yx ’ entry function.
* There may be variations in calculation depending on the insurance company and the timing of interest crediting to the specific annuity. The insurance company may charge a fee for frequent distributions, or impose a surrender charge if the policy is surrendered within 12 months after the most recent interest payment and subject to surrender charge at that time.
Tags: Annuities