Warren Buffett, the 21st century’s best-known investor, extols firms that have a “moat” around them—a barrier that offers stability and pricing power.One way American firms have improved their moats in recent times is through creeping consolidation. The Economist has divided the economy into 900-odd sectors covered by America’s five-yearly economic census. Two-thirds of them became more concentrated between 1997 and 2012 (see charts 2 and 3). The weighted average share of the top four firms in each sector has risen from 26% to 32%…

These data make it possible to distinguish between sectors of the economy that are fragmented, concentrated or oligopolistic, and to look at how revenues have fared in each case. Revenues in fragmented industries—those in which the biggest four firms together control less than a third of the market—dropped from 72% of the total in 1997 to 58% in 2012. Concentrated industries, in which the top four firms control between a third and two-thirds of the market, have seen their share of revenues rise from 24% to 33%. And just under a tenth of the activity takes place in industries in which the top four firms control two-thirds or more of sales. This oligopolistic corner of the economy includes niche concerns—dog food, batteries and coffins—but also telecoms, pharmacies and credit cards.

The ability of big firms to influence and navigate an ever-expanding rule book may explain why the rate of small-company creation in America is close to its lowest mark since the 1970s … Small firms normally lack both the working capital needed to deal with red tape and long court cases, and the lobbying power that would bend rules to their purposes….

Another factor that may have made profits stickier is the growing clout of giant institutional shareholders such as BlackRock, State Street and Capital Group. Together they own 10-20% of most American companies, including ones that compete with each other. Claims that they rig things seem far-fetched, particularly since many of these funds are index trackers; their decisions as to what to buy and sell are made for them. But they may well set the tone, for example by demanding that chief executives remain disciplined about pricing and restraining investment in new capacity. The overall effect could mute competition.

The cable television industry has become more tightly controlled, and many Americans rely on a monopoly provider; prices have risen at twice the rate of inflation over the past five years. Consolidation in one of Mr Buffett’s favourite industries, railroads, has seen freight prices rise by 40% in real terms and returns on capital almost double since 2004. The proposed merger of Dow Chemical and DuPont, announced last December, illustrates the trend to concentration. //

Roughly another quarter of abnormal profits comes from the health-care industry, where a cohort of pharmaceutical and medical-equipment firms make aggregate returns on capital of 20-50%. The industry is riddled with special interests and is governed by patent rules that allow firms temporary monopolies on innovative new drugs and inventions. Much of health-care purchasing in America is ultimately controlled by insurance firms. Four of the largest, Anthem, Cigna, Aetna and Humana, are planning to merge into two larger firms.

The rest of the abnormal profits are to be found in the technology sector, where firms such as Google and Facebook enjoy market shares of 40% or more

But many of these arguments can be spun the other way. Alphabet, Facebook and Amazon are not being valued by investors as if they are high risk, but as if their market shares are sustainable and their network effects and accumulation of data will eventually allow them to reap monopoly-style profits. (Alphabet is now among the biggest lobbyists of any firm, spending $17m last year.)…

Perhaps antitrust regulators will act, forcing profits down. The relevant responsibilities are mostly divided between the Department of Justice (DoJ) and the Federal Trade Commission (FTC), although some …[But]Lots of important subjects are beyond their purview. They cannot consider whether the length and security of patents is excessive in an age when intellectual property is so important. They may not dwell deeply on whether the business model of large technology platforms such as Google has a long-term dependence on the monopoly rents that could come from its vast and irreproducible stash of data. They can only touch upon whether outlandishly large institutional shareholders with positions in almost all firms can implicitly guide them not to compete head on; or on why small firms seem to be struggling. Their purpose is to police illegal conduct, not reimagine the world. They lack scope.

Nowhere has the alternative approach been articulated. It would aim to unleash a burst of competition to shake up the comfortable incumbents of America Inc. It would involve a serious effort to remove the red tape and occupational-licensing schemes that strangle small businesses and deter new entrants. It would examine a loosening of the rules that give too much protection to some intellectual-property rights. It would involve more active, albeit cruder, antitrust actions. It would start a more serious conversation about whether it makes sense to have most of the country’s data in the hands of a few very large firms. It would revisit the entire issue of corporate lobbying, which has become a key mechanism by which incumbent firms protect themselves.

Excerpts from Too Much of a Good Thing, Economist, Mar. 26, 2016, at 23