life of the two CDS contracts. Credit default swaps are also used to structure synthetic collateralized debt obligations (CDOs). Instead of owning bonds or loans, a synthetic CDO gets credit exposure to a portfolio of fixed income assets without owning those assets through the use of CDS. CDOs are viewed as complex and opaque financial instruments. An example of a synthetic CDO is Abacus 2007-AC1, which is the subject of the civil suit for fraud brought by the SEC against Goldman Sachs in April 2010. Abacus is a synthetic CDO consisting of credit default swaps referencing a variety of mortgage-backed securities. Naked credit default swaps In the examples above, the hedge fund did not own any debt of Risky Corp. A CDS in which the buyer does not own the underlying debt is referred to as a naked credit default swap, estimated to be up to 80% of the credit default swap market. There is currently a debate in the United States and Europe about whether speculative uses of credit default swaps should be banned. Legislation is under consideration by Congress as part of financial reform. Critics assert that naked CDSs should be banned, comparing them to buying fire insurance on your neighbor's house, which creates a huge incentive for arson. Analogizing to the concept of insurable interest, critics say you should not be able to buy a CDS—insurance against default—when you do not own the bond. Short selling is also viewed as gambling and the CDS market as a casino. Another concern is the size of the CDS market. Because naked credit default swaps are synthetic, there is no limit to how many can be sold. The gross amount of CDSs far exceeds all "real" corporate bonds and loans outstanding. As a result, the risk of default is magnified leading to concerns about systemic risk. Financier George Soros called for an outright ban on naked credit default swaps, viewing them as "toxic" and allowing speculators to bet against and "bear raid" companies or countries. His concerns were echoed by several European politicians who, during the Greek Financial Crisis, accused naked CDS buyers of making the crisis worse. Despite these concerns, former United States Secretary of the Treasury Geithner and Commodity Futures Trading Commission Chairman Gensler are not in favor of an outright ban on naked credit default swaps. They prefer greater transparency and better capitalization requirements. These officials think