The signal may be fading for Sprint Nextel's chief executive.

The company has begun searching for a replacement for its C.E.O., Gary Forsee, according to the Wall Street Journal. The report cites unnamed "informed people" who say the Sprint board hopes to name a successor by December. It will likely be someone from outside the company.

Investors have become restless as the telecommunications giant has lost customers and seen its share price fall 27 percent since it acquired Nextel in 2005. Ralph Whitworth of Relational Investors, a major Sprint Nextel shareholder, told the Journal he has lost confidence in Forsee. He threatened a proxy fight for board seats unless it addresses the problems with the company's leadership.

The merger with Nextel was done under the leadership of Forsee, who has been at the helm of the company since 2003. Last year, Sprint directors stepped up the pressure on Forsee to fix some of the unresolved problems from the merger.

Since then, Forsee announced new initiatives in the WiMax space, and took steps to improve the company's network technology and customer service. But his efforts have had little impact on Sprint Nextel's share price.