Global ratings agency Standard & Poor’s on Wednesday raised Los Angeles County’s credit rating to AAA, the highest possible credit rating available in the financial markets.

In announcing its decision, the agency attributed the upgrade to the county’s “long-term trend of robust local economic performance from an already strong and very diverse tax base, and an associated strengthening in revenue and tax base that have improved its capacity to meet capital and service priorities.”

Wednesday’s action marks the fourth time that one of the three major credit rating agencies has increased L.A. County’s ratings under the leadership of the current Board of Supervisors and Chief Executive Officer Sachi A. Hamai.

Standard & Poor’s AAA rating is a significant achievement shared by only 12 other California counties.

“As Chief Executive Officer of Los Angeles County, I am deeply gratified by this recognition of our longstanding commitment to responsible fiscal practices,” Hamai said of the AAA rating. “This unprecedented credit ratings upgrade for the County validates our guiding principle: that it takes strong fiscal discipline to realize our vision for ambitious and creative solutions to our most challenging social issues.

“We are the social safety net for more than ten million residents, and this credit upgrade will help us save public dollars that can then be re-invested in housing the homeless, treating the mentally ill, building a more sustainable region, and creating real and positive social change so that our residents can live their best lives,” Hamai said.

In announcing the upgrade, Standard & Poor’s noted that the County has grown and maintained very strong reserves in both the general fund and the Department of Health Services fund.

“The upgrades reflect our view of the county’s long-term trend of robust local economic performance from an already strong and very diverse tax base and an associated strengthening in revenue and tax base that have improved its capacity to meet capital and service priorities,” Standard & Poor’s Global Ratings credit analyst Jen Hansen said.

This marks the second notable increase for Los Angeles County in two months. In June, another leading global credit rating agency, Fitch Ratings, increased the county’s long-term credit rating from AA to AA+.

Fitch attributed that credit ratings upgrade to the combined strength of L.A. County’s continued solid revenue streams, strong economic base, moderately low long-term liability burden and the ongoing progress toward addressing unfunded pension liabilities.

The three major rating agencies—Standard & Poor’s, Fitch and Moody’s—provide independent assessments of the creditworthiness of the county as a borrower, which investors use as a guide to evaluate credit risk.

Government credit ratings are similar to consumer FICO or credit scores. The county’s status as a low credit risk means the interest rate it pays to borrow money is lower than it would be otherwise, thus providing flexibility and security in funding vital services for the County’s constituents. When the county obtains a low-interest rate loan, all county residents benefit.