Charles Munger Jr. has now given a nearly $23 million to an independent committee fighting for a measure that would curtail union political fundraising abilities while opposing Gov. Jerry Brown's tax proposal.

Both initiatives, Proposition 32 and Proposition 30, respectively, go to a statewide vote on Nov. 6.

Munger, a Stanford physicist and the namesake son of billionaire Warren Buffet's long-time business partner, gave another $2 million on Thursday to the Small Business Action Committee PAC, according to a state filing that was released today.

William Oberndorf, the now-retired co-founder of the Mill Valley, Calif., investment firm SPO Advisory Corp., kicked in $1 million to the dual-purpose committee.

Munger's latest contribution follows $10 million donation from Munger earlier this week and two contributions last month that totaled $10 million. He's also given a total $873,000 directly to the Yes on 32 campaign.