The Prosper study I featured yesterday lists the Prosper fees. While it does not attempt to calculate the revenues of Prosper.com it gives some indications regarding the operating costs:

According to Mendelson (2006), the primary costs of Prosper consist of …, (2) a $4 fee for identity authentication, credit pulling, and bank-account setup per active borrower, (3) customer service at the average rate of four interactions per loan and $2 per interaction, and (4) a fixed overhead cost of approximately $3 million per year. …

Given these estimates, it is difficult to measure Prosper accounting in precision. However, there is no doubt that Prosper’s revenue does not cover its full cost (as of February 2008). The difference is met by a large stock of venture capital.

Regarding the Prosper revenues, Mike did a calculation estimating the November 2007 revenues at 114,000 US$. If this is correct, it did not even cover fixed overhead.

Prosper changed fees since that last calculation.