COMCAST said it would buy Time Warner Cable for $45.2bn (€33.1bn) in an all-stock deal that combines the two largest North American cable operators.
The friendly takeover comes as a surprise after months of public pursuit of Time Warner Cable by smaller rival Charter Communications and immediately raised questions as to whether it would pass the scrutiny of anti-trust regulators.
Comcast will pay $158.82 per share, which is roughly what Time Warner Cable demanded from Charter.
The combined company would divest three million subscribers in the US, about a quarter of Time Warner's 12 million customers. Together with Comcast's 22 million video subscribers, the roughly 30 million total would represent just under 30pc of the US pay television video market. The new cable giant would tower over its closest video competitor, DirecTV, which has about 20 million video customers.
If successful, the deal will be the second time in little more than a year that Comcast has helped reshape the US media landscape after its $17bn acquisition of NBC Universal was completed in 2013.
The proposed combination, which would give roughly 23pc of the merged company to Time Warner Cable shareholders, is subject to approval from the US Department of Justice and the Federal Communications Commission. The two companies expect to close the deal by the end of the year.
The new partners are concentrated in different cities. Comcast would fill in its New Jersey and Connecticut portfolio with Time Warner Cable's New York City customers, for instance, and add major markets such as LA and Dallas.