A regulatory filing shows that 3M Co. chief executive George Buckley plans to sell almost one-third of his company stock, worth more than $33 million.

The prearranged plan would have Buckley sell about 350,000 shares of 3M common stock over the next two months. The shares were acquired through stock-option exercises and will be sold in accordance with minimum price thresholds.

The plan was described in a Wednesday filing with the U.S. Securities and Exchange Commission.

Shares of 3M were up 39 cents, or 0.4 percent, to $94.33 in morning trading Thursday.

Buckley became CEO of the St. Paul-based company five years ago. In February he will turn 65, which is 3M's mandatory retirement age.