Costco Wholesale Corp expanded its share buyback authorization and raised its dividend by 17 percent on Tuesday, sending the retailer's shares up 0.8 percent in after-hours trade.

The warehouse club operator said its board of directors approved a stock repurchase program of up to $4 billion, which will replace the existing program that had a remaining unused authorization of about $800 million.

This new program will expire in April 2015.

Costco's board also raised its quarterly dividend to 24 cents per share, payable on May 27 to shareholders of record on May 13, from 20.5 cents a share.

Costco shares rose to $80.40 after the buyback and dividend announcement from their close at $79.78 on the Nasdaq.

(Reporting by Martinne Geller; Editing by Gary Hill)