Mr. Geithner traded barbs with the Republicans, occasionally raising his voice to the point of shouting. During a Joint Economic Committee hearing on Capitol Hill, Rep. Kevin Brady (R.,

• 一些短期美国国债的收益率甚至变为负值，这显示投资者对这种最安全的证券有强劲需求。负收益率表明，投资者为了自己的资金安全，宁愿付钱给美国政府。