BROOMFIELD - James Q. Crowe, the only chief executive Level 3 Communications Inc. has known in its present incarnation as a global Tier 1 telecommunications company, will step down from the position by the end of the year, the company said Thursday, March 7.

The board of directors of Broomfield-based Level 3 (NYSE: LVLT) has formed a planning committee to oversee the leadership transition.

Crowe will assist the board and his eventual successor in the transition, a media release from Level 3 said. The board could decide to move up Crowe's departure, the release said.

Crowe said he and the board have been discussing the transition "for some time," and that he is leaving Level 3 at a time of "financial and operational strength."

Recent stock and revenue data might suggest otherwise. In the past year, Level 3 shares have dropped 15 percent after reaching a high of $27.99. On Thursday, the stock opened at $20.74.

Level 3 also has reported 16 consecutive quarterly losses and made job cuts. It did purchase rival telecom Global Crossing for $2 billion in 2011.

Crowe's history with Level 3 is long and predates its emergence as a telecom company. Crowe became CEO of Kiewit Diversified Group Inc. in 1997, which was then a wholly owned subsidiary of Peter Kiewit Sons' Inc. Kiewit is an Omaha, Nebraska, company best known for construction and large-project management.

KDG, which had some IT and telecom assets, rebranded itself as Level 3 in 1998 and changed its focus to providing telecom and information services.  Level 3 went public on April 1, 1998, and raised $14 billion that year, according to a company history. That year, the company also announced it was moving its headquarters to Broomfield.

Chairman Walter Scott praised Crowe for his work launching Level 3 and building it into a company with a 100,000-mile fiber network that reaches 500 markets.

"It is no exaggeration to say that, without Jim, there would be no Level 3," Scott said.