A public stock offering this year by Facebook Inc., the world’s most-used social-networking site, could boost California’s budget through taxes on capital gains, the state legislative analyst said in a report yesterday.

Facebook, based in Menlo Park, Calif., is considering the largest initial public offering for an Internet company on record, a person familiar with the plans said last year. Facebook seeks to raise about $10 billion in an initial share sale that would value the company at about $100 billion, the person said last year.

Jonathan Thaw, a Facebook spokesman, did not immediately respond to a phone call and an e-mail message requesting comment on the company’s plans.

California Governor Jerry Brown unveiled a $92.6 billion spending plan on Jan. 5 that assumes voters pass temporary increases in sales and income taxes in November. Additional revenue from an initial public offering by Facebook could cushion the blow somewhat, the legislative analyst said in its report.