3.1.4.1. CEO Tenure-to-Age. A CEO who has had five years of tenure at age 65 is likely to be of different quality and have a different
equity ownership than a CEO that has had five years of tenure at age 50. These CEOs likely have different incentive, reputation, and
career concerns. Gibbons and Murphy (1992) provide evidence on this. Therefore, we use the ratio of CEO tenure to CEO age as a
measure of CEO quality, which will serve as an instrument for CEO ownership.