Zuckerberg Won't Sell Facebook Stock for at Least 12 Months

Facebook CEO Mark Zuckerberg has no intention of selling any of his Facebook shares when a lockup expires in late October, according to a filing with the Securities and Exchange Commission.

According to the filing, Zuckerberg said he had no intention of selling any Facebook shares for at least 12 months — a move that could reassure jittery investors.

Zuckerberg holds about 444 million shares of common stock as well as 60 million shares of common stock issuable upon the exercise of an option.

Two directors, Marc Andreessen and Donald Graham, will both sell shares but only to settle tax obligations. The filing said that other than for tax-related purposes, they “have no present intention to sell any shares of our common stock held by them personally.” (Read More:Investor Thiel Unloads Most of His Facebook Shares.)

Andreessen issued a statement saying he will sell only what he needs to cover tax obligations and "not a penny more" and that he plans to hold onto the remaining shares "indefinitely."

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The lockup for employees has also been moved up to October 29 from November 14.

(Click here for an after-hours Facebook quote)

Finally, the distribution of restricted stock is being done in such a way to reduce shares outstanding by 101 million. As the S-1 filing discussed, a number of employees have restricted stock vesting October 23, the same day Facebook said it will report quarterly earnings. Facebook will distribute only 55 percent of those shares and will hold back 45 percent to cover tax charges. (Read More: The Man Behind Facebook’s IPO Debacle.)

“The only real change here is that the outstanding share count will be slightly lower than everybody thought and the free float will be slightly lower than people thought,” Henry Blodget, CEO of Business Insider said in a CNBC interview.

-By CNBC's Julia Boorstin and Justin Menza

Read more Media Money with Julia Boorstin at mediamoney.cnbc.com. Follow Julia on Twitter at @JBoorstin.