Now I am retired, I can safely make a confession: for years, I was stealing a living.

I say so because the general financial advice any retail investor needs is actually very simple:

- Minimize taxes and charges. Avoid expensive fund manager fees. Don't trade very much. Make full use of Isa and Sipp allowances.

- Make the power of compounding work for you, not against you. Start investing as early as you can. And remember that fund managers' fees compound horribly over time; an extra half percentage point in annual fees can easily add up to over £2000 for every £10,000 invested over twenty years.

- Diversify sensibly. Hold equities for growth, and non-equity assets (which might just be cash or your earning potential) to spread risk.

- Invest regularly, via monthly direct debits. The habit of savings is important.

Granted, we can finesse this. History suggests we can use market timing; equity returns have been partly predictable by consumption-wealth ratios, the dividend yield, ten-month moving averages or simply the time of year. And two types of stock have beaten the market on average over the long-term: defensives and momentum: yes, most stock market anomalies are illusory (pdf) or short-lived, but not these two.

But retail investors don't need these add-ons, not least because we've no guarantee that past relationships will continue to exist. Many people can safely invest in tracker funds and cash and get on with their lives. You needn't bother with portfolio optimization. It can't be done. Simple (pdf) diversification works. Satisficing is the best we can do.

Everything useful that needs saying about investing can thus be written in a few words. Beyond this, there are sharply diminishing returns and I suspect even negative ones. Which is why I say I was stealing a living.

And so too have been thousands of finance professionals:

- Equity analysts. "corporate growth rates are random" concluded Paul Geroski in one study (pdf). "There is no persistence in long-term earnings growth beyond chance" found Chen Karceski and Lakonishok in another (pdf). "Firm growth is characterized by a predominant stochastic element, making it difficult to predict" concluded Alex Coad in another survey. All of which means that, insofar as equity analysts are paid to forecast earnings (and in fairness they do other things) they are getting money for nothing. The big price falls we've seen recently in Netflix and Peloton (along others) shows the dangers in relying upon forecasts for earnings growth.

- Economic forecasters. Prakash Loungani has shown that these have consistently failed to predict recessions around the world: they are better at forecasting GDP growth in normal times, but that's when we don't really need forecasts. If you want to know the chances of recession, just look at the yield curve.

- Fund managers. These, said the Financial Conduct Authority in a recent report, "did not outperform their own benchmarks after fees." The "vast majority" of them, said David Blake and colleagues in another "were not simply unlucky, they were genuinely unskilled." Such findings corroborate evidence which we've had for years (pdf) in the US (pdf). Granted, there's some evidence fund managers can pick stocks, but the benefits of this are dissipated by their need to hold more shares to reduce liquidity risk, or by their poor selling strategies.

Many people in finance, then, are simply quacks, snake oil salesmen.

I use the analogy for a reason. Quacks and snake oil salesmen thrived for decades: the market does not always weed out charlatans. Our latter-day snake oil salesmen prosper because they use similar techniques to their 19^th century counterparts, described (pdf) brilliantly by Werner Troesken. They use product differentiation (such as the launch of new funds, be it small cap ones in the 80s, TMT ones in the 90s or ESG ones today); exploit wishful thinking and the public's ignorance or distrust of experts; and they rely upon people not distinguishing between skill and luck.

The analogies between the finance and patent medicine industries aren't perfect, however. One difference is that the finance industry is less competitive. Thomas Philippon (pdf) and Guillaume Bazot (pdf) have shown that the costs of financial intermediation (such as fund managers' fees or spreads between borrowing and lending rates) haven't changed for decades. The IT revolution has done nothing to lower costs for customers.

Huge swathes of the finance industry are therefore failing their customers. This is not because of mis-selling or crime. It happens in the legal everyday operation of the industry.

Which is true in another way - the financing of business. For every £1 banks have lent to UK manufacturing companies they have lent £34 in personal mortgages. And in 2019 (the last normal year before the pandemic) banks' net lending to non-financial companies was just £11.5bn compared to household savings of £72.2bn. The idea that banks use household savings to finance business isn't just wrong in theory (savings don't create loans): it is wrong as a matter of numbers. Banks are property lenders with a casino sideline, rather than financiers of industry.

The financial system, then, does not serve its customers well.

There's another way in which this is true - financial innovation.

As Robert Shiller has shown (pdf) - based on Arrow and Debreu's work in the 50s - financial products could in theory protect individuals from big economic risks. If we could trade securities which were claims on GDP or occupational earnings, people worried about or exposed to downturns could protect themselves by going short. This is especially useful because, given the impossibility of predicting recessions, monetary and fiscal policies are not sufficient protection.

In fact, though, we don't get such useful innovations - or at least not on the scale we need. Instead, we get scams and gimmicks such as ICOs or NFTs.

There's a reason for this. The innovation we get depends upon whether innovators can capture a sufficient fraction of their benefits. They can do so for (say) NFTs, but not for Shiller-type products.

It's tempting to infer from this that we have a financial system which is not fit for purpose. Such an inference is wrong. It is superbly well-equipped for purpose - if that purpose is to funnel wealth from clients (and wider society) to itself.

You might think this claim is a radical one. Maybe, maybe not. It is, however, one that is rooted in wholly conventional economics. You don't need heterodox thinking to challenge the existing order.