Amgen, based in Thousand Oaks, expects to repurchase 9.6 percent of its outstanding shares at a price of $60 per share after asking shareholders to name their price in a buyback auction.

The biotech giant and major Ventura County employer said Dec. 8 it had completed a modified Dutch Auction, where it solicited bids from sellers in a range from $54 to $60 per share.

The company earlier issued bonds at favorable interest rates to pay for the massive buyback. The total cost for the 83.3 million shares will be about $5 billion.

Amgen, with market capitalization before the buyback of more than $50 billion is one of the largest companies in California by stock value.

The company repurchased about 8 million shares in all. Amgen’s share price was up about half a percent to $58.70 in midday trading.