Irvine heart valve maker Edwards Lifesciences Corp. said Tuesday that its board has authorized a new $500 million buyback of its stock.

Edwards said in a release that the program comes on top of $240 million remaining from a separate $500 million buyback program authorized last year.

The device maker plans to buy back about $100 million of additional shares during the current quarter, which ends Sept. 30.

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

Since the beginning of 2011, Edwards’ stock is down about 7%, to a recent market value of $8.4 billion. The stock had seen gains on anticipation for its Edwards Sapien less-invasive heart valve, which is awaiting a Food and Drug Administration decision.

The recent dip on Edwards shares came on concerns about potential stroke risks with the Sapien valve and the general market turmoil over the last two months.