San Diego County's investment pool balance since 2010.
San Diego County’s investment pool balance since 2010. Graphic via Treasurer-Tax Collector’s Office

San Diego County’s investment pool — with 210 public agencies taking part — has gained Fitch Ratings’ highest credit rating for the 20th year in a row.

County Treasurer-Tax Collector Dan McAllister announced that milestone Thursday.

The investment pool earned a “AAA” rating from Fitch, which indicated the pool has the highest underlying credit quality (or lowest vulnerability to default) and a very low sensitivity to market risk.

“Our investment pool reached $11.4 billion in public funds last April, thanks to the diligent management by our investment team,” McAllister said in a statement.

“They value three principles: safeguarding the principal of the invested funds, meeting the liquidity needs of our pool participants, and achieving an investment return with prudent risk management.”

McAllister’s office invests the funds in high quality securities on behalf of the pool’s participants, who use the money for the operational and capital needs of their agencies.

Among the public agencies in the pool are all 42 public school districts, five community college districts, the San Diego Regional Airport Authority, SANDAG, San Diego Metropolitan Transit System, and other public agencies such as cities, fire and water districts.

Besides full-time investment professionals in the county Treasury, an 11-member oversight committee made up of county, school and public agency officials and five public members reviews the county’s investment policy statement annually.

“The AAA rating is not only good for our bottom line, it’s good for San Diego taxpayers,” said Supervisor Dianne Jacob, chairwoman of the county Board of Supervisors. “It gives us the financial flexibility to improve county operations and invest in needed public improvements.”