The ad attacks Brown with some of the same misleading claims used previously by the Whitman campaign.
"As governor, he grew spending and turned a surplus into a deficit," the ad said.
But this ad is independent of Republican candidate Meg Whitman, it's being put forward by the Small Business Action Committee, headed by Joel Fox. He says the ad is not a campaign ad and its purpose is educational.
"This ad doesn't call for someone to be voted for or against, it doesn't call for a vote at all," he said.
Because the ad doesn't specifically say don't vote for Brown or do vote for Whitman, it's considered an issue ad and under the state rules donors may remain anonymous
"I think this is the perfect example of something which doesn't use the magic words, but is nonetheless a functional equivalent of a campaign ad," ABC7 political analyst Bruce Cain said.
Cain says the problem is California's campaign disclosure laws haven't kept up with federal requirements.
Dan Schnur, the newly appointed head of the Fair Political Practices Commission, intends to tighten the rules but not right before the election.
Cain says after November, there is little doubt the rules on issue ad disclosure will be toughened, but not in time to suit Brown's campaign.
"This is pure and simple about organizations who know that if it were out there that they were behind these ads they wouldn't be credible and people wouldn't believe them and they don't want the ad to fail so they don't want to identify who they are," Sterling Clifford from the Brown for Governor Campaign said.
Whitman's campaign declined to comment on the disclosure issue, saying it's an issue for the fair political practices commission.
Fox told ABC7 his donors are afraid of going public for fear of retribution from Brown, but Cain calls that fear 'exaggerated.'