Shares of Aecom (ACM - Get Report) rose 1.8% to $37.20 in premarket trading Thursday after one of the engineering company's largest shareholders sent a letter to the board calling for a strategic review of the company's assets to "unlock value."

The letter from Peter Feld, managing member of the hedge fund Starboard Value, to Michael Burke, chairman and CEO of the Los Angeles-based Aecom, said "we believe that Aecom's market leading franchises are deeply undervalued and that significant opportunities exist within the control of management and the Board of Directors (the 'Board') to unlock value."

"We believe there is a substantial opportunity to drive profitability improvements through integration and operational initiatives," the letter said. "In addition, we believe a more expansive and open minded strategic review of the Company's assets is necessary."

On Monday, Aecom said its board approved a plan to spin off the company's management services segment into a standalone government company.

The letter complained that Aecom's "consistently poor operating history" has resulted in "several years of disappointing shareholder returns." 

"The underperformance is particularly striking in light of the URS acquisition," the letter said, referring to a 2014 agreement, "a transaction that was billed as transformational and highly synergistic."

The letter ends by stating "significant change is urgently needed given the persistent underperformance at the company."

"We look forward to engaging with you and other shareholders to discuss these topics further," the letter said. "Our goal is for Aecom to create long term value for the benefit of all shareholders."

Aecom didn't immediately respond to a request for comment.