Online marketplace lender, SocietyOne is continuing to ramp personal finance volumes, growing its loan book by A$38 million in the September quarter.SocietyOne had personal loan assets worth $350 million at the end of September - more than double the $164 million it had lent out a year ago.The lender has been able to undercut the pricing of major banks by using risk-based pricing to set borrower rates.SocietyOne links borrowers to individual and companies prepared to fund loans.It has a four-tiered risk classification system, which means that applicants with excellent credit histories are offered fixed rates under eight per cent for three year loans.Most personal loans marketed by major banks are currently priced above 14 per cent.According to disclosures on SocietyOne's website, about 15 per cent of the loan book is exposed to borrowers with excellent credit histories(defined by the company as "Tier One" borrowers).Since it launched in August 2012, the marketplace has delivered average annual returns to investors of about 10.6 per cent.