In setting up, and bidding in online auctions, people face difficult strategic decisions. In this study, a Borrower Decision Aid is introduced, which will help formalize the decision making process of the sellers, or borrowers in this case, in one particular P2P loan auction site, Prosper.com. The vast amount of real-life bidding data available in this online auction enables us to build new kinds of tools for decision makers. The Borrower Decision Aid helps the borrower to quantify her strategic options, such as starting interest rate, and the amount of loan requested. We identify which variables concerning the borrower are related to the probability of successfully securing a loan and the final interest rate. (C) 2010 Elsevier B.V. All rights reserved.