Executives come and go at any large organization, but when the company in question is IBM -- and when it loses three high-ranking executives in a single month -- it's only natural to wonder what's going on.

That, in fact, is just what apparently happened at IBM in December, when it reportedly lost Steve Mills, the 43-year company veteran who was most recently executive vice president of IBM Software and Systems, along with Danny Sabbah, its chief technology officer for cloud, and Brendan Hannigan, general manager of IBM Security.

For the past year, Mills had reported to none other than CEO Ginni Rometty herself.

Were the moves simply a natural progression or a sign of something bigger in the works?

"IBM is losing valuable, experienced executives with the departure of Mills and Sabbah," said Charles King, principal analyst with Pund-IT.

While both have made considerable contributions to the company's success, they are also well past the typical retirement age of 60 that IBM recommends for senior executives, King pointed out.

"Mills and Sabbah played instrumental roles in the massive reorg that IBM instituted late in 2014," he said. "Now that that process is essentially complete, they can leave the company knowing that their efforts and vision succeeded."

As for Hannigan, "he did a great job with IBM's security organization, both in integrating the numerous acquisitions the company has made in this area and helping to coalesce these technologies into a solid portfolio," King said.

His departure may simply be part of a long-planned corporate strategy.

Hannigan's replacement -- Marc van Zadelhoff, who joined IBM in 2006 via its acquisition of Consul Risk Management -- has long been considered a rising star at the company, King said. "His move into the GM chair means that IBM now has a leader who intimately understands both the company and the complex security industry."

Rob Enderle, principal analyst with Enderle Group, has a different theory about the triple exodus.

"One of the reasons that folks depart together like this is because they have an idea they want to explore outside of the firm," Enderle said. "Every one of these folks would be a huge asset to a smaller firm, and they’d certainly have the combined financial resources to start something interesting."

Bottom line? "Keep an eye on these three," Enderle said. "The fact they left together suggests they have something else they want to do together, and given their powerful skillset, that 'something' could be really interesting."

IBM did not respond to a request for comment.

(PCW)