As part of an overall stock buyback scheme, Merck (NYSE:MRK) has launched an accelerated repurchase program to buy shares held by Goldman Sachs. All told, the pharmaceutical company will purchase $5 billion worth of its stock from the investment bank.

That figure equates to roughly 99.5 million shares. The transaction is expected to be completed by Nov. 25 of this year.

Merck has been quite busy in the stock buyback sphere of late. As of April 30, the firm's total outstanding authorization for such activity stood at $16.1 billion. In the first four months of this year, it bought back around 17.8 million shares, spending $772 million to do so.