The promise to keep the overnight interest rate low for an extended period was intended to persuade investors that they could achieve higher returns only by buying long-term securities, which would drive up these securities’ prices and drive down their yields. But the current version of this promise – not to raise the overnight interest rate until the unemployment rate drops below 6.5% – no longer implies that short-term rates will remain low for an “extended” period.
在相当长的时期内将隔夜利率维持在低位的承诺本意是让投资者相信他们可以仅靠购买长期证券获得更高回报，这可以促使这些证券价格上涨、收益率下降。但这一承诺的当前版本——在失业率下降到6.5%之前不提高隔夜利率——不再意味着短期利率将在“相当长”的时间内维持低位。