Accounting Fundamentals of the Book-to-Market Ratio
研究发现账面市值比由当前和滞后的市场价值变化决定，账面价值滞后市场价值长达六年，揭示了历史成本会计下账面价值的时效性问题。
The book-to-market ratio is a function of current and lagged changes in market value. The coefficients of correlations between book and market values decline smoothly toward zero as the lag increases. The magnitude and length of the lags are greater, the longer-lived a firm's assets. To understand current book-to-market ratios, one must consider movements in the market value of common equity over the past six years. In other words, market values of common equity lead the book value of common equity by as much as six years. This is striking evidence of the timeliness (or lack thereof) of book values based on historical cost accounting.