Brian Roberts, Comcast's CEO. Getty / Scott Olson US regulators are leaning toward blocking a $45 billion mega-merger between Time Warner Cable and Comcast, Bloomberg reports.

That would deal a blow to a pair of companies aiming to consolidate in the face of the rise of streaming entertainment.

Bloomberg emphasized that no final decision has been made, however.

The transaction, which was announced in February of 2014, has dragged through regulatory approval. It spurred before speculative reports that the TWC-Comcast transaction could be scuttled.

Bloomberg's report during Friday-afternoon trading said a decision could come from regulators in as little as one week.

The fact that regulators may vote against the deal is a surprise.

Earlier on Friday, Time Warner Cable stock was trading close to Comcast's bid of $158.82 a share. That would suggest that the market expected the deal to close.

In February, Comcast's chief financial officer, Michael Angelakis, said the company was "optimistic" and "comfortable” that the merger would close in early 2015.

Opposition to this deal has always been based on the idea that Comcast and Time Warner Cable already provide customers poor service and that they would have less incentive to improve that service after they combined. There would be one less competitor in the market.

Time Warner Cable stock dropped about 5% following the news.