Schmidt owned 7.6 million shares in Google.
Google executive chairman, Eric Schmidt, is planning to sell 42% of his stake in the search company for about $2.5bn.
The company said in a regulatory filing that Schmidt plans to sell 3.2 million shares of stock over the coming year.
Google said the move was part of Schmidt's long-term strategy for individual asset diversification and liquidity.
Using this trading plan, Schmidt can diversify his investment portfolio and can spread stock trades out over a period of one year to reduce market impact, the company said in the filing.
As of 31 December 2012, Schmidt owned about 7.6 million shares in Google, representing 2.3% of the company's outstanding stock.
Schmidt joined Google as chief executive in 2001 and stepped down from the CEO role in 2011 to become executive chairman.
In December 2012, Google's market share dropped to 88% while its search rivals like Bing, and Yahoo increased their overall market share.