Donald Trump remains opposed to AT&T Inc's (T.N) planned $85.4 billion acquisition of Time Warner Inc (TWX.N), Bloomberg reported, citing people close to the president-elect.

Trump believes the deal would concentrate too much power in the media industry, Bloomberg reported.

Shares of AT&T were down 0.3 per cent, while Time Warner's stock was down 1.4 per cent.

Trump during his campaign had said AT&T's proposal to buy the owner of CNN and the Warner Bros movie studio was an example of a "power structure" that was rigged against him and voters.

Trump's transition team was not immediately available for comment.