Commission is zero at almost every major retail broker. That was the entire fight, and it is finished.
For someone buying an index fund twice a year, that is the end of the story. For anyone trading intraday it opened a gap that most platform comparisons still walk straight past. The number that used to decide which broker you signed up with has become the least informative number on the page.
What replaced it never appears in any marketing material. It appears in your fills.
The cost that never reaches your statement
Run thirty round trips in a session. That is sixty executions, and each one landed at a price that was better than, equal to, or worse than what your screen showed at the moment you clicked.
Take a trader working 1,000 shares at a time who loses half a cent per share to slippage. Five dollars per execution. Three hundred dollars across the session. Push that across a full trading year and the platform advertising itself as free has quietly become one of the most expensive things in the account.
There is no line item for it. No notification, no monthly summary, nothing to reconcile. Just a result that sits slightly below the one you thought you were getting.
None of this is an accusation. Slippage comes out of routing decisions, venue access, infrastructure and order handling, which are ordinary commercial choices rather than misconduct. The awkward part is that the trader is almost never in a position to measure any of it.
Four things that decide your fill
Order routing: when you press buy, the order goes somewhere specific. In the United States that destination has often been a wholesale market maker who paid your broker for the flow. Those arrangements sit in quarterly Rule 606 filings that virtually no retail trader opens. Routing decides which venues get a chance to compete for your order, and therefore what price comes back.
Price improvement: the other side of the same coin. How often did your order fill better than the prevailing quote, and by how much? US brokers report this under SEC Rule 605, which the Commission expanded in 2024 to cover more firms and break the data into finer categories. Two platforms with identical fee schedules can produce noticeably different numbers here.
Behaviour under load: a platform’s performance on a quiet Tuesday afternoon tells you nothing worth knowing. What matters is the opening bell, a CPI print, or the morning a widely held name gaps twelve percent. Rejected orders, delayed confirmations and frozen charts are execution costs too, because they change what the trader does in the next thirty seconds.
Order type support: a platform offering only market and simple limit orders is restricting which strategies you can actually express. Brackets, trailing stops, conditional orders and time-in-force settings are not features for professionals. They are risk controls, and their absence turns up as larger losses on the trades that go against you.
Europe took a different route
The gap between American and European practice on this question has widened a lot. Under the MiFIR review the European Union moved to prohibit payment for order flow, with a transition window letting member states that had allowed it wind the practice down through the middle of 2026. The UK’s Financial Conduct Authority arrived at a comparable position considerably earlier.
The practical result is that a European retail trader and an American one are now operating inside two different execution models. European brokers have to demonstrate best execution without the revenue stream that made zero-commission trading economically viable in the US market, and that changes both pricing and routing behaviour.
So jurisdiction has become part of the execution question. Any comparison treating a US-regulated broker and an EU-regulated one as interchangeable products is comparing two things that are no longer alike.
How you would actually test this
You cannot read any of it off a marketing page, which is why platform rankings built on published fee schedules keep arriving at the same top three.
The alternative is dull but perfectly doable. Open a funded account. Place a controlled set of orders. Record the quoted price at submission against the price you actually got, then repeat across order types and across different market conditions, paying particular attention to the first and last thirty minutes of the session when spreads and volume behave least like the rest of the day.
That is the approach behind MyInvestAcademy’s day trading platform comparison, which evaluates platforms through live funded accounts and executed trades rather than published rate cards. Testing this way is slower than reading fee tables and it produces messier results, but it surfaces the differences that a fee table structurally cannot show.
When this matters, and when it does not
Worth being honest about the limits here. If you place a handful of trades a month in modest size, execution quality is a rounding error in your returns and you should optimise for other things: account protections, product range, tax reporting, the quality of the research tools. The broader broker comparison is the right lens for that trader, not this one.
Execution quality starts to dominate at frequency and at size. Somewhere between those two profiles is a line, and most traders assume they are on the wrong side of it.
Three questions that beat any fee table
Where does my order go, and can I see the disclosures? A broker who makes routing data easy to find is telling you something before you have read a single figure.
What happens when the platform is under stress? Look for third-party outage records and user reports from high-volume sessions rather than vendor uptime claims.
Can I place the order I actually want to place? If the order types are missing, the fee schedule stops being relevant.
The zero-commission era fixed a genuine problem. Retail traders had been overpaying for access for decades, and that is worth something. What it also did was remove the one metric everybody understood how to compare, and the industry has been in no hurry to replace it with anything harder to market.
Execution quality is the replacement. It is more difficult to measure, considerably less fun to advertise, and it decides more of the outcome. Right now it is close to the only platform comparison still capable of telling you something you did not already assume.
