There was a moment in the fifth series of the much-loved US sitcom Happy Days when the show began to lose its magic. On holiday in Los Angeles, the Fonz paired his leather jacket with swimming trunks and water-skis, and, in a far- fetched stunt, vaulted over a shark.
In America, when a TV show, or even a company or a brand begins to lose the qualities that made it popular, they call it "jumping the shark". With Apple's share price down more than 20% in the few weeks since it reached its $705.05 peak on the eve of the iPhone 5 launch in September, questions are being asked about whether its happy days are over.
In October 2011, just a few months after overtaking Exxon Mobil as the world's largest company, Apple lost its founder. But the well-oiled machine Steve Jobs had built continued to purr, with one blockbuster product after another. Analysts predicted the shares would reach $1,000, making it the world's first trillion dollar company.
Those who wondered whether Tim Cook could continue to build on the legacy he inherited have had to wait nearly a year for the beginnings of an answer. It is much too early to say if Apple will become the next Sony, the flagbearer for Japanese electronics that became too big to innovate successfully, but the signs are not good. The trouble could be said to have begun not in California but in China's special economic zone of Shenzhen. Here, the hundreds of thousands of workers employed by Apple's contractor, Foxconn, assembled its beautifully-designed gadgets in shamefully oppressive conditions.
Cook reacted decisively, appointing independent auditors and keeping the issue at arm's length, and the scandal did not dent sales. The scales tipped on 19 September, when iPhone owners started to install iOS 6, the latest version of Apple's phone-operating software. As expected, Google's highly popular maps app, which came pre-installed on previous versions of the iOS, had disappeared. What surprised customers was that its replacement, an in-house product which Apple trumpeted as a reinvention of the ancient art of cartography, was badly designed and riddled with errors.
The ruckus cost Scott Forstall, the company's software chief, his job. His departure was used to mask Cook's first major mis-hire as chief executive. Dixons boss, John Browett, brought in to run Apple's retail operation, was let go just nine months after joining.
Meanwhile, Apple's most recent financial results missed profit targets, thanks to slowing iPad sales. Its share of the tablet market has slipped after being squeezed by rival products from Samsung, whose latest Galaxy handset became the world's best-selling smartphone in the third quarter of this year. And sales of the iPhone 5, its banker for the year, are being held back because of production line difficulties.
Apple invented the smartphone, but others are catching up. Google's Android operating system is today in three of every four smartphones. Now Microsoft is spending hundreds of millions trying to establish a critically well received Windows Phone.
But the biggest worry for investors is that Apple has no obviously game-changing products in the pipeline. A year ago the internet was alive with rumours of an iTV. Combining a screen with a computer and serving programmes via iTunes, it would drive a coach and horses through the business models of companies such as Sky and Virgin Media. But the buzz has died down, leading to speculation that Cook has parked the project.
The release of a single app does not decide the fate of a $500bn company, but in years to come the Apple Maps could be seen as when one of America's best-loved brands jumped the shark.
Land Securities enjoys a following wind
This week big construction firm Balfour Beatty issued a heavy profits warning and revealed a falling order book. Its shares fell 18%, to leave it down 7% for the year. But Land Securities, a developer that makes regular use of Balfour's services, sounded cheerful. It is ahead of schedule in signing tenants for its Walkie-Talkie skyscraper in the City and wants to start new developments. Its shares are up 24% since January. What's going on?
With the Olympics a memory, the true climate for contractors is being revealed. Crossrail aside, there just aren't enough big public-sector projects to go around. Big firms are chasing smaller contracts, hurting their pricing power and profit margins. Meanwhile, smaller private developers, who might wish to take advantage of cheaper contracting prices, can't get finance – far too risky from the banks' point of view.
But this situation is great for the likes of Land Securities – a FTSE 100 firm with a conservative balance sheet. It has been expanding aggressively for the past two years and is delighted to find few latecomers to the game.
The art of making money from big office developments in London lies in agreeing construction prices in the slow times. So agree contracts when they are fighting for the work.
But what of the other key to making money from office development – a supply of new tenants for the buildings? With the likes of UBS shedding jobs by the thousand, shouldn't Land Securities have a problem? It appears not. A smart City office lasts about 20 years before it makes sense to tear it down and rebuild. The design improvements mean a tenant can occupy less space with the same number of staff. And, while the big banks are retrenching, there are still insurers, accountants and lawyers who are not.
For Land Securities, the breezes are warming. But contractors have to dream of the day when governments' promises of greater spending on infrastructure turn the cycle in their favour.
Holding court at the Bank of England
With just a few weeks to go before Sir Mervyn King's successor is announced, a rumour reaches our ears that the venerable Sir Terry Burns, former permanent secretary to the Treasury and all-round grandee, did submit his CV, but specified that, because of his advanced age, he would only like to serve for four years.
Since George Osborne is determined to find a candidate to serve the full eight-year term, we hear a compromise has been hatched, under which Burns would be handed the role of chairman of the Bank's court, to oversee whichever whippersnapper is given the big job.
As the Bank takes on its new role as supervisor of the nation's shaky banks, on top of trying to nurse the moribund economy back to health, the thinking goes, a wise chair could play a crucial role.
As to who will win the big prize, our money's on King's affable deputy, Paul Tucker.