I hope everyone survived the tax season!
A few updates:
1) I called Prosper, and they did say that they changed the formatting of their tax reporting because they switched to a new vendor. It's a shame they made this change as previously they would provided two 1099-Bs, one for short term losses, and the other for long-term losses. This made reporting a snap as regulations allow you to aggredate your ST and LT losses in these situations as "Var-l" or "var-S" My software Taxcut allows me to do this in the worksheet.
2) If you have more than one account, they didn't tell me that they aggregated all of the accounts into one consoldated reporting form. I have a NSR account with a totally different log-in, but they only sent me tax forms in my other individual account.
3) I am drawing down my Prosper account, not only for subpar performance, but also they broke my number one rule- if the tax reporting burden is too high, it's not worth my time. I was able to copy all of the data from their 1099-B forms and paste them into a spreadsheet so that I didn't have to manually calculate the cost-basis for 2500 notes individually. As other readers noted, the aggregated sale of ST and LT losses was hidden at the bottom of a page in the 1099-B form. They should have put that data at the front.