Thermo Fisher Scientific Inc. said its board authorized the repurchase of $2 billion of its common shares.

The Waltham, Mass.-based life sciences company still has the authorization to repurchase $250 million worth of stock from its last cohort announced in July 2016 for a total of $1.5 billion.

Thermo Fisher Scientific said this authorization comes without an expiration date. The company will buy from the open market and directly from the sellers.