Chapter 5 Flashcards
how can we compute an equivalent effective interest rate for a longer time period
by raising the interest rate factor (1+r) to the appropriate power
what’s the formula to finding the equivalent n-period effective rate
[(1+r)^n] -1 for effective rate over more than 1 period
or (1+r)^n for EAR over a fraction of a period
what’s APR
amount of simple interest earned in 1 year - amount of interest earned without the effect of compounding even though compounding may occur
must convert APR to EAR for a lot of calculations
because the APR does not reflect the true amount you will earn over one year, the APR itself cannot be used as a discount rate and it is not an effective annual rate. Instead, the APR with compounding periods is a way of indirectly quoting the effective interest rate, r, earned each compounding period.
what’s an implied effective rate
shows the actual interest earned over the compounding period
how to convert APR to its implied effective interest rate
- rate = APR/k compounding periods per year
- then 1 + EAR = (1+r)^k
or 1 + EAR = (1 + [APR/k])^k
why does EAR increase with the frequency of compounding
bc of ability to earn interest on interest sooner
define continuous compounding
compounding of interest every instant - an infinite times in a year
does compounding more frequently have a large impact
no it has a negligible impact on EAR and is rarely observed
whats The three-step method just shown can be applied to any interest rate quote
Step 1: Divide by the compounding frequency to get the implied effective rate per compounding period.
Step 2: Convert the effective six-month rate into a rate per month as the final rate quote has monthly compounding.
Convert the effective monthly rate into a rate quoted per six months compounded monthly by multiplying by 6.
define amortizing loans
a loan where the borrower makes monthly payments that include interest on loan plus some part of the loan balance
how to calculate a loan payment
we first compute the discount rate from the quoted interest rate of the loan, and then equate the outstanding loan balance with the present value of the loan payments and solve for the loan payment.
what’s the outstanding loan balance and how to calculate it
outstanding balance on a loan, also called the outstanding principal, is equal to the present value of the remaining future loan payments, again evaluated using the loan interest rate. We calculate the outstanding loan balance by determining the present value of the remaining loan payments using the loan rate as the discount rate.
define nominal interest rate
interest rate quoted by banks and other financial institutions that indicate the rate at which money will grow if invested for certain period of time
define real interest rate
the rate of growth of purchasing power after adjusting for inflation
what’s the growth of purchasing power formula
growth of money/growth of prices = (1+r)/(1+i)