On the day Funding Circle IPO'd its SME Income Fund Ltd, I came across this excellent article and presentation on the growth of peer to peer lending: I recommend you take a moment to look at the slides.
Fintech analyst Cormac Leech gave an epic presentation at LendIt Europe conference in London last week, answering pretty much every question you might have about the online direct lending market. That covers the new crop of businesses like Lending Club, Funding Circle, RateSetter, and Prosper that let savers lend their money directly to consumers or businesses over the internet. It also covers businesses like iwoca and Kabbage that do balance sheet lending online.
http://uk.businessinsider.com/liberums-cormac-leech-on-online-direct-lending-2015-10?op=0?r=US&IR=T