Category Profit Indicators

Additional Steps to ECM and ARDL

Ednaldo Silva’s blog dated August 21, 2025, contains three sequential equations about the profit rate. My purpose is to demonstrate the connection between his logarithmic 2nd equation and the 3rd equation, referencing the ECM and ARDL econometric models. I used the same econometric reference he cited and adopted some notations of the textbook by Dimitrios Asteriou and Stephen Hall.

Operating Profit Margin is More Reliable than Return on Assets

U.S. 26 CFR 1.482-5(b)(4)(i-ii) claim that the “return on capital employed” (return on assets) is less sensitive to “functional differences” than the operating profit margin or the operating profit markup. This claim is based on the unrealistic premise that “capital flows” to equalize profit rates (return on assets) among companies in the same (or in different) industries by some "invisible hand."

Two-Equations Profit Indicators

Determining an arm’s length profit indicator (profit ratio) requires two equations, and not one equation, as prescribed in financial statement analysis textbooks. E.g., Bernstein (1993), Drake & Fabozzi (2012). An accounting critique of univariate profit ratios is found in Whittington (1986).