The Subprime Crisis Began in June 2007 When Merrill Lynch Asked Bear Stearns’s Hedge Funds for More Collateral

Since the subprime mortgage market began to turn sour in the early summer of 2007, shockwaves have been spreading through all the world’s credit markets, wiping out some hedge funds and costing hundreds of billions of dollars to banks and other financial companies. The main problem lay with CDOs [Collateralized Debt Obligations], over half a trillion dollars of which had been sold in 2006, of which around half contained subprime exposure. It turned out that many of these CDOs had been seriously over-priced, as a result of erroneous estimates of likely subprime default rates. As even triple-A-rated securities began going into default, hedge funds that had specialized in buying the highest-risk CDO tranches were the first to suffer. Although there had been signs of trouble since February 2007, when HSBC admitted to heavy losses on US mortgages, most analysts would date the beginning of the subprime crisis from June of that year, when two hedge funds owned by Bear Stearns were asked to post additional collateral by Merrill Lynch, another investment bank that had lent them money but was now concerned about their excessive exposure to subprime-backed assets. Bear bailed out one fund, but let the other collapse. The following month the ratings agencies began to downgrade scores of RMBS CDOs (short for ‘residential mortgage-backed security collateralized debt obligations,’ the very term testifying to the over-complex nature of these products). As they did so, all kinds of financial institutions holding such assets found themselves staring huge losses in the face. The problem was greatly magnified by the amount of leverage (debt) in the system. Hedge funds in particular had borrowed vast sums from their prime brokers — banks — in order to magnify the returns they could generate. The banks, meanwhile, had been disguising their own exposure by parking subprime-related assets in off-balance-sheet entities known as conduits and strategic investment vehicles (SIVs, surely the most apt of all the acronyms of the crisis), which relied for funding on short-term borrowings on the markets for commercial paper and overnight interbank loans. As fears rose about counterparty risk (the danger that the other party in a financial transaction may go bust), those credit markets seized up.

—Niall Ferguson, The Ascent of Money: A Financial History of the World (New York: Penguin Press, 2008), 271-272.