The relaxation of down payment and documentation standards and a large influx of investors into US housing is likely to have amplified the upward pressure on house prices during the boom, according to a New York Federal Reserve paper published on Monday.

Andrew Haughwout, Donghoon Lee, Joseph Tracy and Wilbert van der Klaauw, the paper's authors, use credit-report data to examine the role played by real estate investors during the housing market crisis. The authors note that in states that