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(CNN Money) -- A great day for Comcast is turning into an even better one for Sky shareholders.

The American cable giant outbid 21st Century Fox and its powerful backer, Disney, on Saturday in an auction for control of the European pay-TV broadcaster.

Comcast's final bid was £17.28 ($22.65), valuing Sky at £30.6 billion ($40.1 billion). That was way up on its previous offer of £14.75, and Sky's closing share price on Friday.

The stock moved fast Monday to catch up, gaining over 8.5% to £17.22 ($22.58) in early London trading.

Comcast has given Sky shareholders until October 11 to accept the offer. Sky's Independent Committee has unanimously recommended Comcast's offer.

Fox is now considering what to do with the 39% of Sky it owns, and which it had agreed to sell to Disney along with its entertainment assets under a deal that was approved by both sides in July.

Fox said it would "make a further announcement in due course."

"Sky is a remarkable story and we are proud to have played such a significant role in building the incredible value reflected today in Comcast's offer," it said.

Sky and its 23 million subscribers are attractive assets to US media companies that want to expand their operations to Europe and bolster their defense against an onslaught from Netflix and Amazon.

It also carries top original shows and valuable premium sports content, such as Premier League soccer.

Comcast CEO Brian Roberts called the auction "a great day for Comcast" in a statement on Saturday.

"This acquisition will allow us to quickly, efficiently and meaningfully increase our customer base and expand internationally," he said.

"We couldn't be more excited by the opportunities in front of us. We now encourage Sky shareholders to accept our offer, which we look forward to completing before the end of October 2018."

Comcast is making a big bet. Its offer is well over twice the price Sky shares were trading at before the latest takeover saga started in December 2016.

— Mark Thompson contributed reporting.