As monetary policy normalizes – a process that has already begun in the United States – the risk-free rate is expected to rise to a level that is consistent with stable 2% inflation, which, in turn, corresponds with a level of unemployment. What precisely that rate is, however, remains uncertain – and extremely difficult to determine, given that it is affected by virtually every aspect of the unfolding growth patterns.
另一个影响市盈率的重要因素是无风险利率。随着货币政策的正常化——美国已开始进入这一阶段——无风险利率预期将上升至与稳定的通胀水平（2%）相一致的水平，这反过来对应着一定水平的失业率。但是，这一利率到底是多少仍不确定——也极难确定，因为增长模式的几乎每一个方面都会对它造成影响。