If you lend them they money and they default, you might lose the money you left them. Although some loans are secured, i.e. backed by assets, liquidation of assets might ultimately not able to pay off the loan completely due to various reasons. Further, it will be a time-drawn issue. Thus, you can consider your loan a write-off and the money is gone; focus on earning back the losses elsewhere. I guess that's the beauty of p2p lending platforms; you get to just loan small amounts per investor; so even if the borrower defaults, you lose $20. $50,. $100. $500, $1000 etc instead of $10k, $100k? Lesson? Invest what you are willing and able to lose.