Asymmetries in the Firm's use of debt to changing market values
研究1984至2013年美国企业数据，发现市场杠杆变化仅在企业股权价值上升时才会引起账面杠杆调整，下降时则无调整，这与增长机会影响最优债务水平的理论一致。
Using a sample of U.S. firms over the period, 1984 to 2013, this study examines the relation between market and book leverage ratios. Unlike Welch (2004) who contends that changes in market leverage do not induce adjustments in book leverage, we find an asymmetric effect. That is, firms adjust their book leverage only when the changes in market leverage are due to increases in equity values. No adjustment is observed when firm equity values decrease. Our results are consistent with Myers (1977) and Barclay et al. (2006) who argue that optimal debt levels decrease with corporate growth opportunities.