Capella Education Co. said Thursday it was extending its share repurchase program with a plan to buy about $50 million of its stock, or about 8 percent of its outstanding shares.

Investors sent the value of its stock sharply higher, as a result. Its shares closed up 9.7 percent at $50.24.

The company’s board decided to extend the buybacks even as Capella, a Minneapolis-based provider of online education services, still has about $6 million left to conclude $50 million in stock repurchases it authorized in August 2013.

Capella launched its stock buyback program in 2008 with plans to purchase $60 million in shares. Directors authorized additional purchases in 2010, twice in 2011 and in 2013.

Since 2008, Capella has repurchased shares worth about $280 million. Its market capitalization as of Thursday was just over $600 million.

As a portion of its overall market float, Capella is one of the most active purchasers of stock of the approximately 90 publicly traded companies based in Minnesota. The company, along with Arctic Cat Inc. and SurModics Inc., reduced outstanding shares by about 28 percent since 2008, when the global economic crisis sent the stock market sharply lower.

A Capella spokesman said the company had no comment on the latest buyback move beyond the formal announcement issued to investors Thursday morning. The board also raised Capella’s quarterly dividend 2 cents to 39 cents.

Capella shares have lost about one-third of their value this year, returning to a level last seen in the summer of 2013, despite stronger operational metrics and gains in profit.

Capella has reported total enrollment gains for Capella University through the first nine months of the year.