Moody's Investors Service on Wednesday upgraded its rating on California's general obligation debt to "Aa3" from "A1," citing the state's improving financial position and employment growth.

The one-notch upgrade stamps California GO debt with its highest rating from Moody's since 2001. That was when the dot-com bust hit the state's economy hard, prompting a series of credit downgrades from which it has been slow to recover due to years of chronic budget problems.