The UK-based European media firm, Sky plc, has received an offer document from 21st Century Fox, initiating a 46-day deadline.
The US company, which already has a 39.1% stake in Sky, has placed an offer of £24.5bn (US$31.55bn) to take over the firm.
The firm has however changed the construction of its offer, from a Scheme of Arrangement to a conventional takeover, Sky News reported.
Fox has not increased its bid of £14 per share, and now has until 22 September to do so in order to compete with rival bidder Comcast CMCSA.L.
The cable operator’s offer for the 60.9% stake in the firm has been recommended by Sky’s independent directors, Reuters claims.
In the remaining period, the two companies have the option to increase their bids. Once the deadline is met, if the situation remains unresolved Britain’s Takeover Panel may launch an auction to end the acquisition deal.