Gary Bei, the top administrator for Sonoma County government's pension fund, has announced plans to retire at the end of the year.

Bei, 58, has led the pension system since 2004. His tenure has been marked by a period of massive funding swings for retirement systems nationwide and bruising debates about the sustainability of taxpayer-backed government pensions.

After years of investment gains in the middle of the past decade, Sonoma County's pension fund — like most others — was hit by unprecedented stock market losses in the 2008 economic downturn. The losses totaled $671 million, or 30 percent, of the pension fund.

The now-$2.05 billion fund has recovered somewhat, though it has relied on record county borrowing to pay off past losses and still shows $527 million in long-term unfunded obligations to retirees.

Bei is set to step down Dec. 24, according to Kiergan Pegg, the county pension fund's board chairman.

"Gary served the board and the retirement association during one of the most challenging times in pension history," Pegg said. "The board was very confident in his leadership during that time."

The past two years have been dominated by state and county attempts to overhaul public pensions to rein in rising taxpayer costs. For Sonoma County's system, those costs — including annual payments on county pension bond debt — are up more than 400 percent since 2000. The costs are driven by investment losses and enhanced benefits which were set by the Board of Supervisors.

The Sonoma County Employees' Retirement Association covers six government agencies, of which the county is by far the largest. It pays benefits to about 4,300 retirees and has about 4,200 current and deferred workers enrolled.

Bei joined as assistant administrator in 2002. He worked previously in financial management at Hewlett Packard, Agilent Technologies and JDS Uniphase.

He was traveling out of the county this week and was not available for comment. His retirement was reported Thursday by Pension and Investments, an industry publication.

An executive search firm, Alliance Research Consulting, is conducting recruitment for the position. Applications are due by July 31. The published salary range for the administrator's post is $168,841 to $205,247.

Pegg said the board hopes to conduct final interviews in mid-September and make a selection thereafter, allowing for some overlap between Bei and the incoming administrator.

Bei is set to receive a pension from the county system. His 2012 pay was $228,024.

(You can reach Staff Writer Brett Wilkison at 521-5295 or