Zero-commission apps made buying shares feel free. The bill did not disappear. It moved somewhere less visible.
A generation ago, buying a few shares meant phoning a broker and paying a commission that could swallow a meaningful slice of a small investment. Today, anyone with a smartphone can open an account in minutes and buy a fraction of a share for the price of a coffee, often with no commission at all. It is one of the clearest examples of financial technology changing everyday behaviour.
But the phrase “commission-free” hides a more interesting story. Platforms still need revenue, and understanding where it now comes from is the most useful thing a new investor can learn.
What technology actually changed
Three things made the shift possible. Cloud infrastructure reduced the cost of running a brokerage to a fraction of what it was. Digital identity checks replaced paper forms and branch visits, so onboarding a customer costs pennies. And fractional shares, made practical by modern back-office systems, let platforms serve customers with very small balances profitably.
The result is genuine progress. Minimum deposits have fallen close to zero, account opening takes minutes rather than weeks, and features that were once reserved for professionals, such as real-time data and automated regular investing, are now standard.
Where the costs went
When the headline commission falls to zero, revenue has to come from elsewhere. The most common sources are worth knowing by name.
The first is the spread, the gap between the price at which you buy and the price at which you could immediately sell. It is paid on every trade and never appears as a line item.
The second is currency conversion. Buying shares listed overseas means converting your money, and many platforms add a margin to the exchange rate each time. For investors who mainly hold international shares, this can easily become the highest cost on the account.
The third is interest on uninvested cash. Platforms often earn more on customer cash balances than they pay out, which is a quiet but significant source of income.
The fourth is subscription tiers and premium features, where the free product is the entry point, and the paid plan carries the margin.
Why the old comparisons no longer work
None of this makes modern platforms bad value. For most people they are far cheaper than what came before. It does mean that comparing platforms by commission alone is now close to meaningless, because the costs that matter are the ones that are not advertised. Independent reviews of the best trading platforms that open funded accounts and record what is actually charged give a much truer picture than a pricing page.
What AI is likely to change next
The next wave is already visible. AI assistants built into investing apps can summarise company reports, explain unfamiliar terms and flag when a portfolio is concentrated in one sector. Used well, these tools narrow the knowledge gap between professionals and private investors. Used carelessly, they can encourage overconfidence, because a fluent answer is not the same as a correct one. The technology lowers the cost of information. It does not lower the risk of the investment.
A simple rule for users
The practical lesson is the same one that applies across consumer technology: when a product is free, find out how it earns its money. In investing, the answer is usually spreads, currency margins and cash interest. Knowing that takes ten minutes, and it turns a confusing market into one that is easy to compare.
The value of investments can fall as well as rise. This article is for general information and is not financial advice.
