Fancy bidding for Sky? Get yourself down to Paternoster Square, just behind St Paul’s Cathedral, on Saturday. The auctioneer promises to get the process wrapped up by the evening so, with a bit of luck, you’ll be home in time to watch the Anthony Joshua fight on your newly acquired TV station.

That’s not wholly accurate, of course. For starters, 21st Century Fox and Comcast, who have been slugging it out for months, will be the only bidders allowed in the auction. And, disappointingly, the Takeover Panel will not require Rupert Murdoch from Fox and Brian Roberts from Comcast to turn up in person at its office to catch the auctioneer’s eye. Instead, investment bankers will relay offers via secure phone lines. But it’s a real auction with real deadlines. Three rounds maximum. Cash only. Best price wins, assuming Sky’s board and shareholders then give a thumbs-up, which is highly likely.

It’s an unusual way to sell a company worth £26bn-ish but a showdown is a sensible way to resolve matters. Neither bidder has declared its offer “final” so let them to show their hands with a clock ticking. All parties, including Disney, which is now the force behind Fox, have agreed to the rules so, unless one side shouts “final” by 5pm on Friday, Saturday’s big match is on. The market expects excitement. The current best bid on the table is Comcast’s £14.75-a-share, versus a market price of £15.81.

As with a conventional auction, both bidders will have to make two calculations. How high is it prepared to bid and how high does it think its opponent will go?

There is one important detail, however. It’s possible that Disney/Fox could play to lose at a high price. Disney has already won the battle with Comcast to buy the bulk of Fox in the US plus Fox’s 39% stake in Sky. So, if Disney decides that’s enough debt-fuelled deal-making for now, it could try to push Comcast to its bidding limit, thereby maximising the value of the Sky holding. It would be a dangerous tactic because it could end up winning. But Disney’s true desire to own all, or any, of Sky is the uncertain factor. Comcast will start as favourite.

Optimism drives Aston Martin’s price tag

Nice cars, famous brand and James Bond drives one. But can Aston Martin, a company with a bad habit of going bust often in the 20th century, really be worth £4bn-£5bn?

That’s the price range for the upcoming flotation and it owes everything to the idea that, having undergone successful repairs under private equity ownership for the past decade, Aston Martin can now offer strong competition to the likes of Ferrari in the luxury car market.

Car manufacturer Aston Martin is set to be floated on the stock market. Photograph: Matt Dunham/AP

Good luck to the ambitious chief executive, Andy Palmer, especially as the firm is a big employer in the West Midlands and south Wales. But floats are about assessing risks, as well as opportunities, and the bottom line here is that Aston Martin made profits of only £76.8m last year. That was a huge improvement on the previous loss of £144m but, in order for the float price to make vague sense, you have to assume acceleration for years and years.

That is precisely what Aston Martin is promising, it should be said: the firm wants to boost production from 6,300 cars this year, to almost 10,000 in 2020 as it enters the SUV market, to 14,000 in “the medium term”. Terrific if it happens, especially as the average selling price last year was £150,000 a car. But it assumes Chinese millionaires, or somebody, will be buying serious quantities, which is an untested proposition.

The other red flag is the mere fact of private equity ownership. The Kuwaiti and Italian crew at Aston Martin have been loyal backers since buying the business from Ford in 2007 so can’t be blamed for wanting to cash a few chips now. But, as a breed, private equity tends to push valuation to the maximum. As with the executive pay arrangements, this float looks over-revved.

When will investors get bored of the board?

Ryanair’s chairman, David Bonderman, deserved the near-30% vote against his re-election. He’s been virtually silent in the past year as the airline as its struggled with strikes, delays and cancellations. Yes, Ryanair remains a hugely successful business and, yes, the chief executive, Michael O’Leary, is not the type to share the limelight. But shareholders want to know that the board is capable of asking, and answering, tough questions. For example: how does Bonderman assess the risk that Ryanair could be damaged by O’Leary’s hardball negotiating stance with the unions?

In the circumstances, Aberdeen Standard Investments was generous to give Bonderman its backing for one more year. He’s had 22 years already. Proceed to the departure gate immediately.