C.R. Bard (NYSE:BCR) said it plans to buy back as much as $500 million worth of its own stock, having spent all but $30 million of a prior share repurchasing plan also worth half a billion.

Companies often buy back their stock when they believe the market is undervaluing share prices, in an effort to raise the price.

Bard announced last January that it would buy up $500 million worth of BCR shares. Yesterday the Murray Hill, N.J.-based medical device company said its board OK’d a 2nd, $500 million program.

"Share repurchases will be made from time-to-time in the open market or through privately negotiated transactions," according to a press release.

BCR shares were trading at $139.05 as of about 11:10 a.m. today, up 1.0%.