Barnes & Noble Inc (BKS) Chairman Leonard Riggio has sold 2 million of his shares in the bookstore chain he founded, lowering his stake in the company to 26.3 percent, according to a regulatory filing on Wednesday.

The sale, coupled with a donation of 160,000 shares Riggio made to a foundation that bears his name, leaves him with some 15.75 million shares in the company he turned into a national chain of big-box bookstores. He remains its biggest shareholder.

Riggio sold the 2 million shares on Tuesday for $13.81 apiece, according to a filing with the U.S. Securities and Exchange Commission.

In February, Riggio said he might make an offer to buy the bookstore chain's retail business but he dropped his plan in August. Barnes & Noble also operates a digital books and device business and a college campus bookstore. All three businesses have been facing sales declines this year.