London: Comcast Corp. formalized its £22 billion ($30.7 billion) bid for Sky Plc, throwing down the gauntlet to Rupert Murdoch’s 21st Century Fox Inc. and Walt Disney Co. as they vie for Britain’s largest pay-TV broadcaster.

Comcast is offering £12.50 per Sky share in an all-cash deal, the Philadelphia-based company said in a statement on Wednesday, confirming a proposed offer it made on 27 February. The offer is at a 16% premium to Fox’s £10.75 per-share bid for Sky.

Media billionaire Murdoch must now decide whether to increase Fox’s bid to stave off Comcast’s challenge, raising the prospect of a bidding war. Fox, which already has a 39% stake in Sky, plans to sell the broadcaster to Disney as part of their $52.4 billion merger announced in December. In a separate statement, Fox said it remains committed to its offer for Sky and is “currently considering its options," with a further announcement in due course.

Sky’s shares rose 3% to £13.40 at 11.03am in London. Since Comcast announced its proposed bid in February, Sky’s shares had been trading at more than £13, at a premium to the Comcast price, as investors expected a protracted battle for the UK broadcaster.

“This might elicit the bidding war," said Alex DeGroote, a media analyst at Cenkos Securities. “We now have a formal proposition, instead of just a suggestion. Sky at these levels is a free bet on the upside."

Comcast said it expects the Sky deal to generate annual run-rate synergies of around $500 million, through a combination of revenue benefits and recurring cost savings.

“We have long believed Sky is an outstanding company and a great fit with Comcast," CEO Brian Roberts said in the statement. “We very much hope that the independent committee of Sky directors will recommend our superior cash offer."

Comcast said acquiring Sky would boost its ability to invest in programming, innovation and would significantly expand its international footprint. About a quarter of Comcast’s sales would come from overseas after a successful acquisition of Sky, compared to 9% currently, the company said.

Fox is still awaiting regulatory clearance in the UK for its Sky bid, with a final decision from Culture Secretary Matt Hancock expected by mid-June. Bloomberg