Amir Khandani

Laboratory for Financial Engineering
MIT Sloan School of Management
One Broadway, Bldg E70-800
Cambridge, MA 02142
Tel: 617/452-3365

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Institutional Affiliation: Massachusetts Institute of Technology

NBER Working Papers and Publications

September 2009Systemic Risk and the Refinancing Ratchet Effect
with Andrew W. Lo, Robert C. Merton: w15362
The confluence of three trends in the U.S. residential housing market---rising home prices, declining interest rates, and near-frictionless refinancing opportunities---led to vastly increased systemic risk in the financial system. Individually, each of these trends is benign, but when they occur simultaneously, as they did over the past decade, they impose an unintentional synchronization of homeowner leverage. This synchronization, coupled with the indivisibility of residential real estate that prevents homeowners from deleveraging when property values decline and homeowner equity deteriorates, conspire to create a "ratchet" effect in which homeowner leverage is maintained or increased during good times without the ability to decrease leverage during bad times. If refinancing-facilitate...

Published: Khandani, Amir E. & Lo, Andrew W. & Merton, Robert C., 2013. "Systemic risk and the refinancing ratchet effect," Journal of Financial Economics, Elsevier, vol. 108(1), pages 29-45. citation courtesy of

November 2008What Happened To The Quants In August 2007?: Evidence from Factors and Transactions Data
with Andrew W. Lo: w14465
During the week of August 6, 2007, a number of quantitative long/short equity hedge funds experienced unprecedented losses. It has been hypothesized that a coordinated deleveraging of similarly constructed portfolios caused this temporary dislocation in the market. Using the simulated returns of long/short equity portfolios based on five specific valuation factors, we find evidence that the unwinding of these portfolios began in July 2007 and continued until the end of 2007. Using transactions data, we find that the simulated returns of a simple marketmaking strategy were significantly negative during the week of August 6, 2007, but positive before and after, suggesting that the Quant Meltdown of August 2007 was the combined effects of portfolio deleveraging throughout July and the first w...

Published: Khandani, Amir E. & Lo, Andrew W., 2011. "What happened to the quants in August 2007? Evidence from factors and transactions data," Journal of Financial Markets, Elsevier, vol. 14(1), pages 1-46, February. citation courtesy of

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