Many large companies fail to pay enough attention to their leadership pipelines and succession practices. That leads to excessive turnover at the top and destroys a significant amount of value—close to $1 trillion a year among the S&P 1500 alone, say the authors of this article. The biggest costs are underperformance at companies that hire ill-suited external CEOs, the loss of intellectual capital in the C-suites of organizations that executives leave behind, and for companies promoting fro...