The Motley Fool's former "When to Sell" seminar was my first gateway to a Foolish life. That seminar held up several items as warning signals, or "red flags," which should prompt you to seriously consider selling a company's stock. One of these -- excessive option granting -- led me to sell my shares of Sportsman's Guide (NASDAQ:SGDE) last spring. Another -- sudden resignation of senior management -- just happened at Burger King.

On April 7, the company announced that Greg Brenneman, CEO since August 2004, was leaving unexpectedly, according to an article in Saturday's Wall Street Journal. His replacement, John Chidsey, was the expected replacement for when Mr. Brenneman eventually left the company, but Mr. Chidsey finds himself in the hot seat probably a lot sooner than he expected.

And a hot seat it is. The company has gone through 11 chief executives since 1989. What is it about the CEO position at this company? The competition, perhaps? McDonald's (NYSE:MCD) certainly isn't making things easy.

I witnessed this firsthand in Pullman, a small college town on the eastern border of Washington state. Over the course of six years in the 1990s, a single Burger King opened twice, one block off the college campus at the edge of frat row. Prime location, right? Each time, within two years, heavy competition from the town's single McDonald's forced the Burger King to close. Price and business execution were the keys, according to the local McDonald's manager. On a broader scale, price competition is not as prevalent today as it has been, because McDonald's has shifted to higher-value items in at least part of its menu.

You cannot buy shares of Burger King right now. That will change later this year, though, when the company issues its initial public offering. Thanks to the required registration statement, the company's financials for the last five years are available. Unfortunately, the company lost money for the first three of those five years. However, Burger King has since turned around, growing revenue by 11% in 2005 and increasing net income ninefold. The registration statement pointed out the importance of Mr. Brenneman in this effort. And to be sure, consistency in leadership is likely to play a role, at least in some capacity, in dictating strategy aimed at creating success on a business execution level.

Which again raises the question: Why did Mr. Brenneman suddenly leave? The company says that it's better to change CEOs before the public offering. That may very well be true, but has the company finished its turnaround -- a process in which the prior CEO was cited as integral? Twenty months, not even seven quarters, seems a bit on the short side to declare the job finished.

For those interested in purchasing Burger King once it becomes public, I'd recommend serious consideration of sudden change at the top, and the company's increasing difficulty in keeping a long-term CEO. In the Foolish seminars I took, I was taught to seek companies with stability and tenure at the top. Burger King, with its revolving CEO door, doesn't fit that bill. If you invest in this company when the time comes, I'd advise stepping carefully.

For further fast-food Foolishness, order up one of these:

Fool contributor Jim Mueller has sworn off French fries, although he hasn't yet kicked the fast-food burger cravings. Jim doesn't own shares in any company mentioned, all according to our disclosure guidelines.