An International Monetary Fund paper published on Wednesday shows lightly regulated non-bank mortgage originators contributed disproportionately to the recent boom-bust housing cycle in the United States.

Jihad Dagher and Ning Fu, the paper's authors, use county-level data on mortgage originations to examine the market share of independent non-bank lenders and how their increased market participation contributed to the subprime mortgage crisis in the US.

The authors show the relationship between