Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Advanced Energy Industries (NASDAQ:AEIS) fell 13% early Tuesday and then recovered to close down around 6.5% after the power conversion technology specialist announced that its CEO of three years, Garry Rogerson, has decided to step down.

So what: Only a few weeks ago, Advanced Energy shares plunged 21% in a single day after the company released mixed first-quarter results and disappointing forward guidance. Still, Rogerson elaborated, "Having made enormous strides on our strategic plan to drive revenue growth, expand margins and increase cash generation, I believe this is a great time to begin a new chapter -- both for our company and for me."

Now what: But the market obviously isn't as optimistic about seeing more management turnover right now. Remember, one of Advanced Energy's co-founders, Douglas Schatz, already retired from the company's board in March, albeit admirably citing a desire to spend more time handling his charitable foundations. Nonetheless, the move resulted in a downgrade today from analysts at Needham, who noted concerns that these high-level departures over such a short time period could cause major disruptions at Advanced Energy.

Even so, note that Rogerson has no intention to leave the company in a lurch and will continue to serve as CEO until a successor is found. In addition, it appears much of this pessimism is priced in, with shares currently trading around 9.6 times next year's estimated earnings. Management turnover or not, I still think Advanced Energy is worth a look for patient, long-term investors.