economically plausible是什么意思啊？

问题如下：

Next, Bader applies the Grinold–Kroner model to estimate the expected equity returns for the various markets under consideration. For Country A, Bader assumes a very long-term corporate earnings growth rate of 4% per year (equal to the expected nominal GDP growth rate), a 2% rate of net share repurchases for Country A’s equities, and an expansion rate for P/E multiples of 0.5% per year.

Using the Grinold–Kroner model, which of the following assumptions for forecasting Country A’s expected equity returns is plausible for the very long run?

选项：

A.Rate of net share repurchases

B.Corporate earnings growth rate

C.Expansion rate for P/E multiples

解释：

Correct Answer: B

Country A’s long-term corporate earnings growth rate of 4% per year is equal to the expected nominal GDP growth rate of 4%, which is an economically plausible long-run assumption. The only very long-run assumptions that are consistent with economically plausible relationships are %ΔE = Nominal GDP growth, %ΔS = 0, and %ΔP/E = 0, where %ΔE is the expected nominal earnings growth rate, %ΔS is the expected percentage change in shares outstanding, and %ΔP/E is the expected percentage change in the price-to-earnings ratio.

A is incorrect because a 2% rate of net share repurchases would eventually eliminate all shares, which is not an economically plausible very long-run assumption. The only very long-run assumptions that are consistent with economically plausible relationships are %ΔE = Nominal GDP growth, %ΔS = 0, and %ΔP/E = 0, where %ΔE is the expected nominal earnings growth rate, %ΔS is the expected percentage change in shares outstanding, and %ΔP/E is the expected percentage change in the price-to-earnings ratio.

C is incorrect because Country A’s perpetually rising P/E would lead to an arbitrarily high price per currency unit of earnings per share. The only very long-run assumptions that are consistent with economically plausible relationships are %ΔE = Nominal GDP growth, %ΔS = 0, %ΔP/E = 0, where %ΔE is the expected nominal earnings growth rate, %ΔS is the expected percentage change in shares outstanding, and %ΔP/E is the expected percentage change in the price-to-earnings ratio.