Irvine-based Edwards Lifesciences Corp. said today that its board authorized a $750 million buyback of its stock.

Shares of Edwards were up 6% to a market value of $8 billion in midday trading.

The heart valve maker said in a release that it still had about $140 million of its current $500 million share repurchase program that was authorized in September 2011. Edwards said it expects to use the remainder of that authorization in the current quarter.

Investors generally like stock buybacks because they prop up the value of a company’s stock by shrinking the pool of outstanding shares.

Edwards’ stock is down some 37% since the beginning of 2013. It took a large hit in late April after reporting disappointing first-quarter earnings and lowering its full-year outlook.

Edwards also said that its chief financial officer, Thomas Abate, was retiring from his position.

Abate, 59, became Edwards’ financial chief in 2006 and will stay in his position until a successor has been found. The heart valve maker retained Hinsdale, Ill.-based executive search firm Crist/Kolder Associates to find Abate’s successor.