Omaha, Nebraska. A place of pilgrimage, 35,000 shareholders of Berkshire Hathaway have come to pay homage. A global event, but still quintessentially American. On Friday, the group’s products are on sale; See’s candies and Fruit of the Loom t-shirts are the most popular. Precision Castparts, the manufacturer of specialist components for aeroengines which is Mr Buffett’s latest acquisition, puts on a bewildering display.  A model railroad represents the Burlington Northern Santa Fe network. Sadly, there are no discounts on Netjets cards. In the evening, we drink cocktails and eat junk food in a tacky marquee alongside a display of expensive jewellery. (25% off for Berkshire shareholders)

The truly devout queue from 4am outside the CenturyLink Arena, to secure seats near the front.  Many of these determined attendees are Chinese, with insufficient skills in English language to follow the lengthy proceedings;  they seek only proximity to the Master.  Saturday begins with a movie, full of in jokes about personalities in the Berkshire family.

And then the high point of the ritual; journalists, analysts and shareholders fire questions at Warren Buffett and his partner, Charlie Munger for five hours. The stamina of Mr Buffett, 85,  and Mr Munger, 92, would be  astonishing even if they were younger men. They engage in easy, witty repartee; if Mr Buffett is prolix at times, Mr Munger is sardonically concise.

The business model is as simple as it has been effective  – a closed end fund with a strategy of long term commitment and close engagement with investee companies. What is surprising is that the success of Berkshire Hathaway has produced so little imitation. Other conglomerates have employed financial engineering and imposed supposedly transferable management skills but Mr Buffett eschews creative accounting and has no illusions that he will manage Precision Castparts better than the incumbents. His method is to find well run businesses and give them more freedom than they would enjoy on public markets.

Yet the closed end fund is out of fashion; financial advisers and regulators prefer the open ended model, with all the constraints on long term investment which requirements for valuation and liquidity involve. Within the EU, closed end vehicles are to be complex products, supposedly dangerous investments for small shareholders such as those who flock to the CenturyLink Arena to applaud Mr Buffett.

The control mechanisms within the group are tight but informal. The exchanges with analysts demonstrate that the tiny headquarters staff in Omaha is very familiar with what is happening in the operating businesses. But Mr Buffett is at pains to emphasise the absence of formal reporting lines and control systems, central budgets and targets, and complex incentive schemes. In a revealing moment Mr Buffett was asked about the absence of conventional due diligence in his acquisition process; Berkshire had made bad acquisitions, he acknowledged, but never one that could have been avoided by the kind of information due diligence might have revealed.

The overriding ethos of Berkshire Hathaway’s shareholder weekend is of membership of a cult, an ethos engendered by this informality but also key to its effectiveness. Berkshire’s success is based on the trust relationships which so evidently exist between the group, its operating companies, and its investors. Berkshire’ s display is a world apart from the notion of the firm as nexus of contracts among people who find it mutually advantageous, for the moment, to do business with each other. And  a world apart from the place to which most recent financial innovation has been leading us.

Mr Buffett’s particular genius is not that he is a great stock picker. His genius lies in the relentless clarity of his appreciation of the nature of business – focus on competitive advantage, find good management, give that management freedom with accountability only for results. And in his creation of a business model which follows those insights.