Google chairman to sell $2.5 bn of shares

The sale amounts to 42 percent of Schmidt's 7.6 million Class A and Class B shares in the company, a 2.3 percent stake in the company, but 8.2 percent of voting power.

The sale is part of a pre-arranged trading plan for Schmidt's "long-term strategy for individual asset diversification and liquidity," according to the filing.

"Using this trading plan, Eric can diversify his investment portfolio and can spread stock trades out over a period of one year to reduce market impact."

Google's share price climbed 1.5 percent Friday to a new all-time record of $785.37, putting the value of the shares Schmidt will sell at $2.51 billion.

In its September 2012 billionaires list -- when Google shares crossed the $700 line for the first time -- Forbes ranked Schmidt 138th in the world, with his fortune worth $7.5 billion.