We estimate the effect of CEO succession planning on shareholder value in the US S&P 1500 firms. We use hand collected CEO succession data from 2005 to 2012 and find more than 25% of firm don’t manage their succession planning well. Among firms experience poorly managed CEO succession planning, the median duration on CEO vacancy or potential vacancy is 139 days. Shareholder value lost 118.5 million $ following the the failed CEO succession. The value loss cannot be explained by other factors that previous literature suggested. This decrease in firm value only happens in short-run. In the long-run, firms with poorly managed CEO succession planning do not underperform.