The asset-backed securities were based on the overly optimistic figures, which improperly inflated the true collateral behind them, the investors say.
But unlike common stocks, whose ownership has traditionally been hidden, mortgage-backed securities are based on loans whose details were long available in public land records kept by county clerks, who collect fees for each filing.
Cantor Fitzgerald, the biggest broker of American Treasury bonds, was located at the top of one of the towers, and the primary futures market for these securities was based in another building at the bottom of the centre that was also destroyed.
"Cryptographic security is based on conjectures that are unproved and seemingly very difficult to resolve," Cohn went on.
The yield on a commercial mortgage security is based on the rent or revenue collected on the underlying properties.
Mr. Bush's belief that the United States has the right to use force against nations that it believes may threaten American security is based on the assumption that Washington can make accurate judgments about how serious such a danger is.
The entire basis of our law enforcement system, and indeed much of our thinking about security, is based on an assumption that people are motivated to preserve their own lives and well-being.
Wright's sense of security is based on the knowledge that Radio 3 exists not to deliver the BBC a good news story in the quarterly audience Rajar figures but to underpin the cultural heritage of the nation.
Much of our election security is based on "security by competing interests".
The multilevel security is based on assigned keys to different nodes at different levels.
