The hockey stick Phillips curve and the effective lower bound
研究了名义利率有效下限与外部融资成本相互作用如何削弱金融冲击的通缩效应，导致菲利普斯曲线在有效下限时平坦、正常时期陡峭的曲棍球棒形状，并削弱前瞻指引的效果。
We show that the interplay between a binding effective lower bound (ELB) on nominal interest rates and the costs of external financing weakens the disinflationary effect of financial shocks. In normal times, the real costs of production factors dominate in firms' marginal costs and are therefore key for inflation dynamics. In contrast, financing costs normally play a subordinate role as higher credit spreads are balanced-out by lower nominal rates. At the ELB, however, higher spreads following financial shocks can offset the effect of lower production factor costs on firms' price setting. The relationship between inflation and output hence features a hockey stick shape: the Phillips curve is flat at the ELB, but conventionally upward-sloping during normal times. This mechanism also weakens the power of forward guidance at the ELB, since such policy reduces spreads and financing costs.