Optum Company, which is part of UnitedHealth Group (UNH), to grow in size with the acquisition of Surgical Care Affiliates (SCAI).

Under the terms of the agreement, SCAI shares will be purchased for $ 57 / share, which implies a 17% premium to Friday's closing price, and the purchase will be financed through a combination of cash and shares. In particular, from 51% to 80% of the purchase price will be financed by UNH ordinary shares, while the remaining part will be paid in cash. UnitedHealth Group have the opportunity later to determine what portion of the transaction will be paid in shares.

The transaction is expected to be completed during the first half of 2017. UnitedHealth Group estimates that the purchase will have a neutral impact on its adjusted net earnings per share in 2017 and light in 2018.

UNH shares fell in premarket trading to $ 161.58 (-0.51%).