UPDATE 1-T-Mobile to offer free Netflix to some family plan customers

(Adds COO comment, shares' action)

Sept 6 (Reuters) - T-Mobile US Inc said on Wednesday it will offer a free subscription to video streaming service Netflix Inc with its unlimited data family plans in a push to lure more subscribers in a highly competitive U.S. wireless market.

T-Mobile, the No. 3 U.S. wireless carrier by subscribers, has been taking share from larger rivals through cheaper prices and added perks. It already allows users to stream video from Netflix without using their data.

Mike Sievert, T-Mobile's chief operating officer, characterized the agreement with Netflix as a "big investment" during a call with reporters. Even so, T-Mobile said the deal will not affect its financial forecasts.

Users on the carrier's unlimited family plan, known as T-Mobile ONE, will get access to Netflix at the same price of $40 per line for a family of four, T-Mobile said in a statement.

Shares of Verizon were off 0.5 percent at $47.12 in midday trading. T-Mobile was down 0.6 percent at $63.27 and Netflix was up 0.6 percent at $175.61. (Reporting by Aishwarya Venugopal in Bengaluru and Anjali Athavaley in New York; Editing by Shounak Dasgupta)