Costs
Zero commission changed behaviour, not cost
Removing the visible price of a trade did not make trading free. It removed the friction that used to stop you.
The points below about commission-free trading are ordered by how much difference they make, not by how often they get repeated.
What matters most
- Spreads, currency conversion and tax remain even where commission is zero.
- Lower friction raises trading frequency, which carries its own cost.
- A visible charge functioned as an unintended behavioural brake.
The commission was doing two jobs
A dealing charge was a cost and also a moment of hesitation, a small price that made you ask whether the trade was worth it. Removing it removed both, and the second was arguably worth more to the average long-horizon investor than the first. This is a case where a cost was providing an accidental service.
Nothing has replaced that friction unless you add it yourself.
What remains after commission
The spread between buying and selling prices persists on every transaction and is not usually presented as a charge. Currency conversion on foreign holdings, custody arrangements and taxes on transactions in some markets all continue to apply. How a zero-commission provider earns revenue is a fair question and the answer differs by market and regulation.
Where it helps most, the practical point is that a trade with no stated fee is not a trade with no cost.
Friction is a design decision
Trading apps are designed to be quick, and quickness is a product feature that raises the number of decisions you make. Interfaces that celebrate transactions, display constant price movement or offer prompts to act are shaping behaviour by construction. This is not sinister; engagement is what most consumer software optimises for.
For most people, it is nonetheless working against the specific behaviour a long-horizon investor needs.
Restore the friction deliberately
A written rule that no trade happens on the day it is thought of removes most impulsive activity at no cost. Using a provider whose interface is dull, or keeping the app off your phone, works through the same mechanism. Some people write the intended trade and the reason in a note and revisit it a week later, at which point most disappear.
In practice, these techniques work because the impulse is short-lived and the plan is not.
The genuine improvement
Cheaper transactions are a real gain for infrequent investors, particularly those contributing small amounts regularly. A monthly purchase that once carried a meaningful charge is now viable at small sizes in many markets.
The gain accrues to people whose behaviour did not change and is lost by those whose behaviour did. Which group you are in is decided by your rules rather than by the pricing.
If that does not fit your week, it is not a failure of willpower.
Watch for the adjacent products
Low-cost trading is often bundled with features that carry considerably more risk, such as leverage, derivatives or highly concentrated instruments. Availability and regulation of these differ substantially between countries, and some are unsuitable for long-horizon investing by design. The absence of a commission says nothing about the suitability of what is being traded.
On an ordinary week, anything involving borrowed money or complex instruments warrants regulated advice before it is considered.
Everything above, in order of what to do first
- The commission was doing two jobs. A dealing charge was a cost and also a moment of hesitation, a small price that made you ask whether the trade was worth it.
- What remains after commission. The spread between buying and selling prices persists on every transaction and is not usually presented as a charge.
- Friction is a design decision. Trading apps are designed to be quick, and quickness is a product feature that raises the number of decisions you make.
- Restore the friction deliberately. A written rule that no trade happens on the day it is thought of removes most impulsive activity at no cost.
- The genuine improvement. Cheaper transactions are a real gain for infrequent investors, particularly those contributing small amounts regularly.
- Watch for the adjacent products. Low-cost trading is often bundled with features that carry considerably more risk, such as leverage, derivatives or highly concentrated instruments.
The takeaway
The commission was a brake. If you removed it, install a new one.
Pick the one that costs you least, and let the rest wait.
Questions readers ask
Are commission-free platforms worse?
Not inherently, and cheap dealing genuinely helps regular small contributions. The question is whether the reduced friction changes how often you trade.
How do I know what a trade really cost me?
Compare the price you paid to the price at which you could have sold at the same moment. That gap is the spread, and it applies whether or not a commission is charged.
