Update 11.10pm: Liberty Media has announced that it has agreed a deal to acquire Formula One.
Original story: The first part of a multi-billion-euro deal that could revolutionise how Formula One is consumed and run was set to be signed on Wednesday evening and officially announced on Thursday.
Press Association Sport understands American entertainment and media giant Liberty Media will buy in the region of 10% of F1's parent company Delta Topco from the British private equity firm CVC Capital Partners with an agreement to purchase CVC's remaining shares, subject to regulatory approval, early next year.
CVC Capital Partners, which has controlled the world's most popular motor sport series for a decade, currently owns 35% of the shares but those shares have majority rights under the company's voting rules.
With F1 valued at more than €7billion, CVC's stake will cost Liberty Media around €2.5billion, although it is unclear if it will command a premium for its voting rights or if Liberty Media will try to buy out the remaining shareholders.
One of those shareholders is F1 chief executive Bernie Ecclestone, the 85-year-old former car salesman who has run the sport for 40 years and built it into the global entertainment business it has become.
A source close to the English billionaire told Press Association Sport that Ecclestone has been asked to remain in his role by the prospective new owners but could not confirm reports that he has been offered a three-year transitional deal.
Neither CVC Capital Partners nor Liberty Media would comment on the status of their long-running negotiations, or what role the charismatic but controversial Ecclestone would play going forward.
His business model of exclusive broadcasting deals based on national territories and big fees from race hosts has clearly been very successful - as the huge dividends CVC Capital Partners has earned from the sport would suggest - but there is an inescapable feeling that it has run its course.
Liberty Media, which is owned by American media mogul John Malone, and its sister companies have interests that span from baseball's Atlanta Braves to Virgin Media, and Malone owns shares in ITV, Eurosport and Formula E.
As a major investor in the internet, many observers expect Malone to move F1 more in that direction, which would not be difficult as Ecclestone has made no apologies about ignoring the digital revolution.
Liberty Media will also want to grow F1's presence in the United States, where it has traditionally struggled against home-grown alternatives, although the US Grand Prix in Austin has been a relative success.
And F1 fans should expect more innovations with gaming technology and virtual reality, as well as a much more coherent marketing effort with the drivers and teams. But the days of terrestrial broadcasters like the BBC, ITV or current domestic home Channel 4 providing free-to-air coverage on Sunday afternoons might be numbered.
That said, there are still hurdles for Liberty Media to clear.
Malone's many interests mean the proposed deal could run into competition law problems with British and European Union regulators, and there is already an EU investigation into how F1 allocates prize money between the teams, many of whom are losing money hand over fist.
The same can be said of the venues that host the races, as crowd numbers have dipped in recent seasons as ticket prices have risen and the racing has become more predictable. Even Ecclestone has noticed that, which has led to a testy relationship with CVC Capital Partners, who have given a good impression of an owner more than happy to watch its prize asset sweat while it counts the money.
Another potential obstacle for the takeover is the fact that motor sport's governing body the FIA holds a 1% stake in Delta Topco, although it is hard to see how it could make a conflict-of-interest complaint when it is so clearly conflicted, too.
And then there is the need to negotiate a new prize-money-and-rules deal with the teams in time for the 2021 season.
But one thing is certain: this deal marks a crossroads moment for the sport and Ecclestone, who turns 86 next month. F1 is about to change one way or another.