Why did the us investors demand repayment of debt by europeans?

Wall Street tactics akin to the ones that fostered subprime mortgages in America have worsened the financial crisis shaking Greece and undermining the euro by enabling European governments to hide their mounting debts. As worries over Greece rattle world markets, records and interviews show that with Wall Street’s help, the nation engaged in a decade-long effort to skirt European debt limits. One deal created by Goldman Sachs helped obscure billions in debt from the budget overseers in Brussels.