Its offer of £17.28 per share values the company at more than £30.45 billion. Fox offered £15.67 per share.
The three-round auction was orchestrated by the Takeover Panel, which saw no movement in the battle to takeover the broadcaster.
However, the Murdoch Family Trust, which is in the process of selling the majority of 21st Century Fox to Disney, still owns 39 per cent of Sky. The Murdochs would then hold 5% in Disney.
Rupert Murdoch had been hoping that he would be able to take full control of the broadcaster he had established as a single channel European cable service in the 1980s, before commencing a four-channel satellite service from the Astra satellite in 1989.
Comcast had previously bid £14.75 per share, but had received relatively few acceptances, despite being ahead of the £14 per share bid by Fox.
The Sky board is now likely to recommend acceptance of the offer.