# What is the term for this rate?

Let say I lend money to someone \$100 for 5 years at 12% per year.

If I lend it at annual amortization, I will get \$12 in the first year as interest. My return on capital is 12%.

If I lend it at monthly amortization, I will get \$10.28 in interest in the first year. My return on capital 10.28%

What is the 10.28% called?

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Your capital outstanding doesn’t remain constant in #2

Right. The capital outstanding is \$85.81.

10.28/85.81 = 11.979% <- is there a term for this?

OP:  I’m trying to reproduce your interest and principal figures and am having difficulty.

FYI, here’s what I get using my trusty BA II:

N=60, PV=100, set to END

P/Y=C/Y=12  PMT = 2.2244 First year interest 11.16 principal = 84.47

P/Y=12, C/Y =1 PMT = 2,1935 First year interest  10.58 principal = 84,259

As rawraw pointed out, the outstanding principal will change with each payment, so in your monthly example, it is not correct to assume that the outstanding principal is \$100 for the whole year when calculating the rate of return.  As a matter of fact, the outstanding principal will always earn 12%.

“Mmmmmm, something…” - H. Simpson

pheonixza wrote:
What is the 10.28% called?