Shares of semiconductor manufacturer AMD were up Wednesday after a big stock buyback authorization. Here's what that means.

Advanced Micro Devices shares jumped Wednesday, as the chip designer said its board approved a fresh $6 billion share buyback program.

AMD said on Wednesday that its board of directors approved $6 billion in share buybacks. The stock climbed 8%. The authorization is in addition to $4 billion in existing approved share repurchases, the company said.