There are two types of auctions on Prosper: Direct P2P auctions and Open Market auctions.
Bidding on Direct P2P Loans:
In a Prosper borrower Direct P2P auction, lender members bid the amount they are willing to commit and the minimum yield percentage they are willing to receive. Bidding is now based on the yield percentage instead of the borrower’s stated interest rate. The yield percentage on Direct P2P loans is equal to the Borrower’s interest rate, minus Prosper’s 1% servicing fee. Because servicing fees reduce the effective lender yield on Direct P2P loans below the interest rate the borrower pays, the yield percentage already factors in the effect that the servicing fees will have on the yield.
Each borrower listing will show the maximum interest rate the borrower will accept. Bidding on the listing starts at the yield percentage that provides the maximum interest rate set by the borrower. When the total amount of all bids placed in the auction equals or exceeds the initial loan amount, further bids have to be placed at least 0.05% below the current winning yield percentage, bidding down the borrower’s interest rate. In the event that two lenders bid the same yield percentage, the lender who bid earlier wins. The lenders that bid the lowest minimum yield percentage at the end of the auction are the winning bidders. The final yield percentage is the minimum yield percentage for which there is sufficient participation among bidders to accommodate the requested loan amount at the end of the auction period.
Bidding on Open Market Loans:
The bidding process for Open Market listings focuses on the projected "yield to maturity" of the remaining payments of the Open Market loan, rather than the borrower’s final interest rate. The loan seller offering the Open Market loan for sale sets an initial sale price and an initial yield. The yield is calculated as the internal rate of return of the anticipated cash flows assuming all loan payments are made as scheduled. The initial sale price may be different from outstanding balance of the loan, and the initial yield percentage may be different than the borrower’s interest rate. The yield percentage is based on the relationship between the original loan's outstanding principal balance and the sale price in the listing; as the sale price goes up, the yield percentage goes down, and vice-versa.
Depending on the relationship between the yield percentage and the outstanding principal balance, a loan will be sold at a premium or a discount. If the initial sale price is greater than the principal balance, the initial yield percentage will be lower than the borrower’s interest rate, and the loan will be offered at a premium. If the initial sale price is less than the principal balance, the initial yield percentage shown will be higher than the borrower’s interest rate (provided the lower price is low enough to offset the effect of the reduction in the effective yield resulting from servicing fees), and the loan will be offered at a discount.
Lenders bid by specifying an amount to invest and the minimum yield percentage the lender is willing to receive. If the total amount of all bids placed is less than the initial sale price, new bids can be placed at or below the initial yield. When the total amount of all bids placed in the auction equals or exceeds the initial sale price, further bids have to be placed at least 0.05% below the current winning yield percentage. In the event that two lenders bid the same yield percentage, the lender who bid earlier wins. If the listing receives sufficient bids to match the necessary sale price of a loan at the winning yield percentage prior to the end of the auction, once ended, Prosper will purchase that loan from the listing loan seller and issue corresponding Notes to the winning lender member bidders. The final yield percentage determined from the auction bidding process on an open market listing is the interest rate that will be set forth in the Open Market Note corresponding to the open market loan described in the listing.
If any listing does not receive bids totaling 100% of the loan amount at the time the listing ends, your money will be immediately transferred back to your Prosper account.