I'm fact checking my analysis, so there's only one possible answer in that I'm either right or way out in left field (wrong).
A friend of mine mentioned this bitcoin lending site and I looked at it to see if the returns they're promising are correct. When I look at this loan for this question's purpose, I see that it offers a 19.47% return (this is how their interest rates are calculated). What I see is that the borrower borrowed 3 BTC and paid back the 2.99998200 BTC plus 0.37685100 in interest. That is a 12.561775% return, not 19.47%, based on my math and this is a one-year loan (they adjust when it's less than a year).
Now, it's possible that the user paid some early, which would have reduce his later payments, but I haven't heard back from the company when I asked them about this several weeks ago, so I wanted to fact check the math I'm doing because I'm getting a ~7% miss. Thanks!