Billionaire Sean Parker, the former president of Facebook, has donated $500,000 to promote an initiative to legalize recreational marijuana for adults in California, Forbes reports.

The funds went to a newly formed committee called Californians to Control, Regulate and Tax Adult Use of Marijuana While Protecting Children. It has received a total of $1.25 million so far, the article notes.

The donation was listed in state campaign finance records filed Thursday, the article notes. The measure would make it legal for adults 21 years and older to possess, use and purchase up to one ounce of marijuana. The initiative would impose a 15 percent sales tax, as well as state cultivation taxes. The measure could bring in more than $1 billion in state and local tax revenue, according to legislative analysts.

California’s Attorney General cleared the Adult Use of Marijuana Act to move forward last week. The campaign needs 365,880 signatures to qualify for the November ballot.