When is trade mutually beneficial?
The presumption among economists is that trades are generally beneficial for both parties. Each person trading will only do so if they think that they will be better off after the trade. I find it helpful to categorize objections to trade so that it is clear to see under what circumstances trade is harmful and when it is beneficial.
There are three main scenarios when trade is not mutually beneficial:
1. A trader does not get what they expect.
2. A trader is forced into an agreement.
3. The trade creates negative externalities.
Information and Expectations
When people trade, they imagine a future with and without the trade and evaluate those hypothetical worlds. For example, when you are considering buying a candy bar, you imagine a future of eating the candy bar and compare it with an imaginary future without the candy bar. Those two futures are compared and you select the one which is more appealing. The correctness of the decision you make depends on the accuracy of your expectation of the future.
People’s expectations can be incorrect because of fraud, they could be ignorant of what they will get from the trade, or they could simply not enjoy the result of the trade as much as they thought they would. Limited information is a permanent feature of human experience, and so is not a market failure, per se, but it can cause trades to be harmful.
If someone says that information is causing trades to by systematically harmful, they must either claim that the harm is greater than the total benefit of having the market at all, or propose an alternative institution that improves the flow of information. Often the proposed replacement for markets do not solve in the information problem, and so do not improve outcomes.
Forced exchange is not really trade, but I include it because sometimes people consider it a sort of trade. If a trade helped someone, they would not need to be forced to do it. Some examples indlude slavery, colonial resource extraction, and eminent domain.
Negative externalities occur when any trade between two people hurts a third person. Economists usually have a threshold before they consider something an externality, since every trade affects someone else at least a little. The classic example of a negative externality is pollution. When someone produces something that generates pollution, they and their customers only suffer a fraction of the negative side effects from the pollution. Trades with positive externalities are still mutually beneficial.
From Munger’s blog, Euvoluntary Exchange:
An exchange is “Euvoluntary” if:
(1) conventional ownership
(2) conventional capacity to buy/sell
(3) absence of regret
(4) no uncompensated externalities
(5) neither party coerced by human agency
(6) neither party coerced by circumstance; the disparity in BATNAs is not “too large” (opportunity cost not too low)
For more on Euvoluntary exchange, listen to this podcast.