Order routing for active traders: smart vs. direct routes, queue position and fees
Where an order goes changes whether it fills, where it waits in line and what it costs. Smart routes optimise a broker's criteria; direct routes give you control and the responsibility that comes with it.
Start in plain English
When you press buy, your broker or platform sends the order somewhere: an exchange, an ECN-style venue, a wholesaler, or a router that splits it across several. That choice is order routing. For a scalper trading a few cents, it decides three things: whether the order fills, where it waits in line if it rests, and what fee or rebate it carries.
The core idea: a smart route optimises the broker's criteria; a direct route optimises yours, if you know what you are doing. Neither is free. A direct route to the venue showing the best price can arrive after that size is gone. A smart route can split your order and pay more in fees to fill it. Fill probability, queue position and fees trade off against each other, and the trade-off changes with the stock and the second.
ECN fees covers the per-share cost math; Marketable limit orders covers the price ceiling, and the Market vs. limit orders lesson in US Day Trading Fundamentals covers the basics. This lesson adds the destination.
Two paths from the same start
All prices, sizes and fees in this example are Illustrative. Saltmarsh Devices and the venue labels are fictional.
The setup at 10:07:15 ET. Saltmarsh trades $7.40 × $7.41. Level 2 shows 800 shares offered at $7.41 on EXCH1, 300 on EXCH2, and 1,500 at $7.42 on ECNB. The trader wants 625 shares and sends a direct immediate-or-cancel buy to EXCH1, limit $7.41, because EXCH1 shows enough size at the best price.
Saltmarsh Devices (fictional), Level 2 at 10:07:15, ET (Illustrative)
| Side | Price | Size | Source |
|---|---|---|---|
| ask | 7.41 | 800 | EXCH1 |
| ask | 7.41 | 300 | EXCH2 |
| ask | 7.42 | 1,500 | ECNB |
| ask | 7.44 | 2,000 | EXCH2 |
| bid | 7.40 | 1,200 | EXCH1 |
| bid | 7.40 | 600 | ECNB |
| bid | 7.39 | 2,500 | EXCH2 |
| bid | 7.37 | 1,000 | EXCH1 |
Venue labels are fictional. The trader sends a direct IOC buy for 625 shares to EXCH1 at $7.41. The same book starts Path A, Path B and Path C.
The plan, written before 10:07:15. Entry 625 shares at $7.41. Stop $7.33. Target $7.57 (2R). Planned risk $0.08 per share, $50. Costs: $0.005 per share round trip (Illustrative). Rule for partial fills: do not chase; trade the shares filled and keep the stop.
Path AThe size is still there
The order reaches EXCH1 while the 800 shares are still displayed and fills all 625 at $7.41. Price trades up to $7.58 at 10:12 and the $7.57 target fills.
Path BThe size is gone, and the trader chases
Another order takes most of EXCH1's offer a few milliseconds earlier. The IOC fills 200 shares at $7.41 and the rest is cancelled. The offer is now $7.43. Breaking the plan, the trader sends a second order and fills 425 shares at $7.44. Average price $7.4304. Price fades; the $7.33 stop fills at $7.32.
Path CThe size is gone, and the plan holds
Same partial fill: 200 shares at $7.41. The trader follows the no-chase rule. Price reaches $7.57 and the 200 shares exit at the target.
The review note for all three starts the same: "Direct IOC to the venue showing size; plan followed at entry." Path B shows that a partial fill is not a small problem when it triggers a chase; Path C shows its cost when it does not. The rest of this lesson covers how routes differ, how queues work, what fees and rebates do, and how to read your broker's routing disclosures.
Smart vs. direct routes
| Smart route | Direct route | |
|---|---|---|
| Who decides the destination | The broker's or platform's router | You, per order |
| What it optimises | The router's criteria: fill rate, price, fees, rebates, payment for order flow, depending on the broker | Your criteria, if you set them correctly |
| Typical behaviour on a marketable order | Splits across venues showing the price, may sweep several levels up to your limit | Goes to one venue; fills what is there; the rest rests or is cancelled |
| Typical behaviour on a resting order | Picks a venue to post on, sometimes moves it | Posts where you sent it |
| Your responsibility | Knowing what the router optimises | Knowing every venue's fees, order types and rules |
US rules add a constraint to both. Under Regulation NMS Rule 611, trading centers must have policies designed to prevent trade-throughs of protected quotations: an execution at a worse price than a displayed protected quote elsewhere. An intermarket sweep order (ISO) lets a router take the best prices on several venues at once without waiting on each. In June 2026 the SEC proposed rescinding Rule 611 and the related lock-and-cross rule; as of 2026-10-05 that is a proposal, not a final rule.
Queue position
A resting limit order joins a queue. On US exchanges the general order is price, then display, then time: better prices first; at the same price, displayed orders before non-displayed; among those, earlier orders first. So:
- Joining a bid that already shows 20,000 shares means waiting behind all of them on that venue.
- A non-displayed order waits behind every displayed order at its price. Iceberg orders covers this.
- Moving or replacing an order usually sends it to the back.
Queue position is why two traders bidding the same price on different venues can get very different fills.
Adding vs. removing liquidity
Most exchanges use a maker-taker model: orders that remove displayed liquidity pay an access fee, and orders that add liquidity can earn a rebate. Some venues invert this. Whether your broker passes these through depends on your fee plan; ECN fees covers the plans.
Regulation NMS Rule 610(c) caps the access fee for taking a protected quotation. The cap in force as of 2026-10-05 is $0.003 per share for quotes of $1.00 or more and 0.3% of the quote price below $1.00. The SEC's 2024 amendments lower it to $0.001 and 0.1%, but by an order of June 11, 2026, compliance is postponed until the first business day of November 2027.
On a 10-cent scalp, a taker fee on entry and exit is a real share of the edge: $0.006 per share round trip is 6% of a $0.10 gross move (Illustrative rate).
Payment for order flow and routing disclosures
Many retail brokers route most customer marketable orders to wholesalers, which can pay the broker for that flow. Direct-access brokers usually let you choose a venue and pass through exchange fees instead. To see what your broker does (rules as of 2026-10-05):
- Rule 606 reports. Every broker-dealer publishes a quarterly report on where it routed customers' non-directed orders, including the net payment for order flow it received, within a month after the quarter ends. Customers who place not-held orders can request a detailed report on their own orders.
- Rule 605 reports. Monthly execution-quality statistics; the SEC's 2024 amendments, with a compliance date of 2026-08-01, expanded the firms that report them.
Neither report tells you how a particular order fills. They tell you what the router is built to do.
Route rejections
A direct route can be rejected where a smart route would not be: a post-only order that would take liquidity, a venue that is not open in premarket, an order outside LULD bands, or a short sale under SSR priced at or below the national best bid. Test routes in a simulator first; the DAS lessons Order types and time in force and Order query and cancel cover the mechanics on that platform.
Observe vs. infer
At 10:07:15 in the Saltmarsh example (fictional; all figures Illustrative):
| Observed | Inferred | Why it is not established |
|---|---|---|
| 800 shares offered at $7.41 on EXCH1 | "My 625 shares fill there" | Other orders can reach the venue first |
| My route is direct IOC | "I control the outcome" | You control the destination, not the race |
| The spread is one cent | "Costs are negligible" | Fees per share and partial fills are separate costs |
What shifts the odds
These are hypotheses to record, not findings: displayed size relative to your order; how fast the quote is changing; how many venues show the price; time of day; whether the stock is near a halt band.
Cost of being wrong
Using the Saltmarsh plan (Illustrative):
| Outcome | Shares | R against planned $50 | Dollars after costs |
|---|---|---|---|
| Path A: full fill, target | 625 | +1.94R | +$96.88 |
| Path B: partial, chased, stopped | 625 | −1.44R | −$72.13 |
| Path C: partial, no chase, target | 200 | +0.62R | +$31.00 |
| Full fill, stopped with 1¢ slippage | 625 | −1.19R | −$59.38 |
How many trades before this means anything
Fill rates by route are easy to count. Over 20 direct IOC orders, 14 full fills (70%) has a 95% interval of about 48% to 85% (Wilson, computed on hypothetical counts). Compare routes on your own log, not on one bad fill. See How many trades before your numbers mean anything.
What this lesson does not claim
- It does not recommend smart or direct routing, any broker or any venue.
- Fee rates are Illustrative; your broker's schedule decides your costs.
- Rule descriptions are summaries checked on 2026-10-05; the Rule 611 rescission was a proposal at that date.
- Saltmarsh Devices and the venue labels are fictional.
Go deeper
- FennEdge first. The DAS course lessons Order types and time in force and Order query and cancel show how routes and order types are set on that platform.
- Off-exchange fills. Where retail orders go when they do not reach an exchange: Dark pool prints.
- Tick size and fee caps. The 2024 amendments tie tick size and access fees together: Tick size.
- Slippage. Measuring fills against the arrival quote: Slippage.
Exercises
Six exercises follow this lesson: three concept checks, one calculation comparing route fees, one scenario on choosing a route, and one practice task. Exercises, answers and progress are available after signing in.
Practice task: log 20 routed orders. In a simulator that models routes, or with very small live size if you already trade, record 20 orders with every column of the FennEdge practice log: download the practice log (CSV), with a column guide. Use setup_tag = routing-test and record route, requested size, filled size and the arrival quote in conditions, and fees net of rebates in fees_usd. Keep the log separate from the Trading Journal, which holds only real broker-synced trades.
Primary sources
- SEC Regulation NMS: Rule 600 (definitions, including intermarket sweep order), Rule 610, Rule 611, Rule 606 (eCFR).
- SEC. Release No. 34-101070 (September 18, 2024), amendments to minimum pricing increments and access fees.
- SEC. Exemptive order, Release No. 34-105656 (June 11, 2026), postponing compliance to the first business day of November 2027.
- SEC. Release No. 34-105655 (June 11, 2026), proposed rescission of Rules 611 and 610(e).
- SEC. Release No. 34-104147 (September 30, 2025), Rule 605 amendments compliance date.
Sources checked 2026-10-05. Saltmarsh Devices, venue labels, quotes, fills and fee rates in this lesson are fictional and Illustrative. This lesson is education, not a recommendation to buy or sell any security or to use any broker or route. Past patterns do not indicate future results.