The debate over America’s stock-market structure is often presented as a technical argument about exchanges, routing systems and market-data costs. For wealth advisors, however, the more important question is much simpler: will investors continue to receive the best available price when their orders are executed?
That question is now being revisited as Trump administration regulators move to eliminate the longstanding “trade-through rule,” a provision designed to prevent trading venues from executing orders at prices inferior to the best publicly displayed quote elsewhere.
The Securities and Exchange Commission proposed eliminating the rule in June. SEC Chairman Paul Atkins, who has long favored lighter-touch regulation and opposed the rule when he previously served as an SEC commissioner, argues that removing it would simplify market structure and reduce costs.
There is a legitimate case for modernization. The U.S. equity market has become extraordinarily fragmented, and maintaining connectivity and market-data feeds across dozens of trading venues is expensive. But advisors should be careful about translating lower costs for market participants into lower costs for investors.
Those are not necessarily the same thing.
For advisors, the proposed change is therefore less about taking a position in a regulatory dispute and more about understanding how execution quality could evolve—and whether existing fiduciary processes are sufficient to detect the difference.
What the Trade-Through Rule Actually Does
The trade-through rule is intended to prevent an investor’s order from being executed at a price worse than a better publicly quoted price available on another exchange.
Consider a simplified example. Suppose IBM stock is quoted at $70.00 on one exchange and $69.99 on another. An order to buy IBM shares generally should not be executed at $70.00 when a better displayed price of $69.99 is available elsewhere.
The principle is straightforward: an investor should not lose a penny simply because their order was routed to the wrong venue.
That protection becomes more complicated in today’s fragmented market.
There are now 18 stock exchanges, compared with eight in 2005. Most of the newer venues account for less than 1% of U.S. trading volume. Yet brokers and trading firms may need connectivity and pricing information from numerous venues to comply with the existing framework.
That creates a paradox. A rule designed to protect investors has also contributed to a market structure that is expensive and increasingly complex to administer.
Robinhood, for example, has argued that the costs associated with forced connectivity, exchange proliferation and complexity now outweigh the benefits of the rule.
That argument deserves consideration.
But advisors should recognize the distinction between reducing the cost of complying with a rule and eliminating the investor protection embedded in the rule.
The Real Issue Is Execution Quality
For most investors, the relevant outcome is not how many exchanges exist. It is whether their trades are executed efficiently.
That means advisors should think about execution quality more broadly than the quoted price alone.
A $100 stock purchased at $100.01 rather than $100.00 may appear trivial. Across a diversified portfolio, however, thousands of trades and millions of dollars in transaction volume can make seemingly insignificant differences meaningful.
Moreover, the displayed quote is only one component of execution quality. Speed, liquidity, fill probability, price improvement, market impact and execution certainty all matter.
This is where the debate gets interesting.
Removing the trade-through rule could theoretically give brokers and trading venues more flexibility to route orders based on a broader range of factors rather than being constrained by the best displayed quote. That flexibility could produce efficiencies. A venue displaying a slightly inferior price might, for example, offer better execution probability or lower overall transaction costs.
But flexibility also creates more room for conflicts.
Once a broker is permitted to route an order away from the best displayed price, an advisor has to ask a more consequential question:
Why was that decision made, and who benefited from it?
That question goes directly to the heart of an advisor’s fiduciary responsibility.
Why This Matters to RIAs
For modern advice firms, the proposed change should reinforce an important principle: execution quality should be measured, not assumed.
Many advisors reasonably rely on their custodians, broker-dealers and trading platforms to handle order routing. That is appropriate. Advisors do not need to become specialists in market plumbing.
But they do need to understand the processes governing client trades.
If the regulatory framework changes, advisors should expect greater variation among custodians and trading providers in how orders are routed and how execution quality is demonstrated.
That makes due diligence more important.
Advisors should be asking custodial and trading partners questions such as:
- How are orders routed under the new framework?
- What percentage of orders receive price improvement?
- How frequently are orders executed away from the best displayed quote?
- What criteria determine routing decisions?
- How are payment-for-order-flow or other economic relationships incorporated into routing decisions?
- How is execution quality monitored across different market conditions?
- What reporting will advisors receive to evaluate execution quality?
The goal is not to demand that every trade receive the single best displayed price under every circumstance.
The goal is to establish that the firm’s trading process consistently seeks best execution and that there is evidence to support that conclusion.
The Danger of Focusing Only on Trading Costs
One potential mistake would be to assume that eliminating the trade-through rule automatically makes investing cheaper.
The SEC’s argument is partly built around reducing the costs created by today’s fragmented market. Those savings could be real. But the economic benefit ultimately depends on where those savings accrue.
If exchanges, brokers and market makers save money but investors receive less price improvement or somewhat worse execution, the investor has not necessarily benefited.
For advisors, this is an important lesson in evaluating financial-industry efficiency.
A lower operating cost somewhere in the investment ecosystem does not automatically translate into a lower total cost for the client.
The relevant metric remains the client’s net outcome.
That means advisors should resist overly simplistic claims on either side. Eliminating the rule is not inherently anti-investor. Nor is it inherently pro-investor.
The outcome will depend on how market participants respond to the additional flexibility.
Fragmentation Is the Larger Structural Problem
There is another reason advisors should pay attention: the trade-through debate is really a debate about what America’s equity-market structure should look like.
The proliferation of exchanges illustrates the unintended consequences of trying to optimize one part of the system.
In 2005, the U.S. had eight stock exchanges. Today there are 18. Many have very small market shares, yet their existence can add technological, connectivity and data costs.
This raises a legitimate policy question: has market structure become too complicated for the incremental benefits it provides?
If the answer is yes, simplifying the system could ultimately benefit investors.
But advisors should also recognize that complexity is not necessarily the enemy. Competition among trading venues can create incentives for better pricing, liquidity and innovation.
The challenge is finding the point at which competition produces meaningful benefits rather than simply adding layers of infrastructure and cost.
That is a market-design question regulators will have to answer. Advisors, meanwhile, need to focus on the consequences for their clients.
What Advisors Should Do Now
There is no reason for advisors to change trading practices simply because a regulatory proposal has been introduced. But there is a strong reason to strengthen oversight.
First, review your firm’s best-execution policy. Make sure it clearly identifies the factors used to evaluate execution quality and does not implicitly assume that compliance with a particular market-structure rule is equivalent to best execution.
Second, engage custodians and trading providers. Ask how their routing policies would change if the trade-through requirement disappears. The answers may reveal meaningful differences among providers.
Third, request better reporting. Advisors should be able to evaluate execution quality using actual data rather than relying solely on assurances that a platform provides competitive execution.
Fourth, establish a baseline before the rules change. If possible, record current measures such as price improvement, execution speed, fill rates and transaction costs. That creates a benchmark against which future performance can be evaluated.
Finally, prepare to explain the issue to clients without turning it into a regulatory lecture.
Clients are likely to understand the basic concern immediately: “Will my trades still get a good price?”
The appropriate answer is not that regulators guarantee the best price. It is that the advisory firm has a process for selecting and monitoring trading providers and evaluating whether client orders are being handled in the clients’ best interests.
That is a much stronger fiduciary conversation.
The Advisor’s Advantage Is Better Oversight
Ending the trade-through rule could ultimately make the U.S. equity market more efficient. It could also create new opportunities for market participants to optimize routing and reduce infrastructure costs.
But there is no guarantee that every efficiency gained by the industry will flow through to investors.
That is why advisors should avoid treating the proposal as simply another Washington regulatory fight.
The more important development is that execution quality could become less standardized and potentially harder for investors to evaluate.
For sophisticated wealth firms, that creates an opportunity rather than merely a risk.
Advisors who can demonstrate that they actively monitor execution quality—and understand how their custodians and trading partners make routing decisions—will be better positioned than firms that simply assume the infrastructure is working in their clients’ interests.
The trade-through rule may disappear. The advisor’s responsibility does not.
If anything, a less prescriptive market structure makes the advisor’s oversight role more important. The ultimate standard should remain the same: clients deserve a trading process designed around their interests, supported by evidence, monitored over time and evaluated on outcomes rather than regulatory compliance alone.
