Any asymmetry of information between buyer and seller is morally wrong.

Are you familiar with the ancient Roman myth about a group of fishermen who caught and cooked some turtles?

The turtles turned out to be inedible, and the group was discussing how to dispose of them when the god Mercury passed by. Seeing an opportunity to offload their disastrous dish, they invited him to eat with them. However, Mercury was wise to their tricks and forced them to eat the turtles instead.

Although they might not be dealing with turtles and Roman gods, modern-day salespeople could learn a lot from this story. Why?

Well, this myth establishes an important lesson that the fisherman learned the hard way: it's immoral to disguise a sales pitch as well-intentioned advice.

Sadly, in today’s commercial world, many people do just that.

For instance, when the author worked for an investment bank, he frequently saw the underhand tactics that traders used to sell their excess or unwanted stocks to clients.

Instead of being honest about why they wanted to sell the stocks – that is, they had a surplus – the traders told clients the stocks would be great for their particular portfolios, that their value would almost definitely increase, and that they would sorely regret missing such an opportunity. In other words, the traders held back important information about their true reasons for selling and made their desperate sales pitch and psychological manipulation seem like good advice.

But is there really something wrong with this? After all, their behavior was legal, and we’re all familiar with these sales tactics. Interestingly though, while this behavior may be legal in many secular countries, it’s much less acceptable under some religious legal systems.

For instance, Sharia law, the Islamic legal code, contains the concept of Gharar.

This term refers to an asymmetry of information between two agents. If one agent, the seller, has much more information about the transaction than the other agent, the buyer, then the seller could be said to have too much certainty about the outcome of the transaction, and the buyer too little. In this case, Gharar would exist in the transaction, and thus it might be forbidden from taking place until the information asymmetry was redressed, and the buyer was given more information.

Therefore, in the example above, although the traders’ behavior is permitted in some countries, it could be found legally and ethically wanting in others.