...Anybody have any guesses why high rate prime grade loans default...
There's already been some talk about this in bidding strategy discussions. The advice usually given is, avoid loans where the rate is unusually high for the credit grade, because there's something wrong there. Possible explanations:
1. The borrower is only an "A" on ScoreX-- their FICO score is much lower, so they can't get a decent rate anywhere else, which is why they're willing to settle for a high rate on Prosper.
2. The borrower is only an "A" on Experian-- there are some negative marks showing on the other Credit Reports, so, again, the borrower's credit is worse than it appears, and that's why they're willing to settle for a high rate.
3. The borrower is desperate for the money and needs it fast-- never a good thing.
4. The borrower is a scammer. They don't care what rate the loan is at, because they're not planning on paying it back.
5. The listing itself is not good-- there are red flags, but lenders overlook them due to the high rate, thus funding poor loans that would not have funded with a lower rate.
...and lower rate subprime loans are less likely (to default)?
Subprime loans that offer lower rates have to really go through a ringer and lots of scrutiny before they fund. This means that only the best ones make it through-- the ones that are indeed less likely to default.
Also there's the thing about borrowers who don't have a lot of money being able to repay a low rate loan, which will have a lower payment, when they might not be able to repay a higher rate loan with a higher payment.