Bruce Zimmerman, who oversees the state agency that manages the massive combined endowment for the University of Texas at Austin and Texas A&M University, has resigned.

Zimmerman has run the University of Texas Investment Management Company since 2007. Over that period, the total value of the assets that UTIMCO oversees grew from $23.5 billion to nearly $37 billion, according to the UT System. He said in a brief phone interview Monday that he felt it was "time to move on."

"I have been there for nine years and I am just delighted to have had the job," he said.  

But, he added, "Change is inevitable."

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"The UTIMCO staff and Board, and everyone associated with the UT and A&M Regents and Systems, are remarkable people contributing so much to the state," Zimmerman said. "While I will miss working with my colleagues, I have great optimism about UTIMCO’s future and I am excited to begin the next chapter in my life."

UT System leaders praised Zimmerman for his contributions to their system. UT-Austin and A&M have the two of the largest endowments of any public universities in the country. UTIMCO's biggest source of money is the Permanent University Fund, which is supported by 2.1 million acres of state land in West Texas that generates massive oil and gas royalties. Two-thirds of the money from the fund goes to the UT System; one-third goes to the A&M System.  

“Bruce earned his reputation as a strong, skilled investment manager and we are grateful for the excellent work he has done for public higher education in Texas,” said UT System Board of Regents Chairman Paul Foster. “He has steered the ship through good economic times and bad, always preserving and enhancing precious assets that allow us to provide unmatched opportunity for Texas students.”

Zimmerman's annual salary was $750,000 per year, and he regularly received bonuses that pushed his compensation into seven figures, an arrangement that drew criticism from some state leaders. UT System officials defended Zimmerman's pay, saying that investors managing assets the size of UTIMCO's in the private sector made far more. 

Disclosure: The University of Texas at Austin, the University of Texas System, the Texas A&M University System, Paul Foster and Bruce Zimmerman have been financial supporters of The Texas Tribune. A complete list of Tribune donors and sponsors can be viewed here