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Active Trading
Best Brokers for Execution Quality, Speed and Order Routing
Nearly every broker here is paid for order flow, including Fidelity since April 2026. The real difference is whether you can route around it. Interactive Brokers Pro, Fidelity Active Trader Pro, TradeStation, TradeZero and Lightspeed let you choose the venue. For most orders, the fill price matters more than milliseconds. Based on Q2 2026 Rule 606 reports.
Which Broker Fits How You Trade
Almost every broker here is paid for order flow, including Fidelity since April 2026. What differs is whether you can route around it. These picks come from each broker's Q2 2026 Rule 606 routing report and platform documentation.
Multi-venue smart routing
Interactive Brokers
SMART routing across 80+ exchanges. IBKR Pro doesn't sell orders to wholesalers (IBKR Lite does), and you can direct orders to a venue yourself.
Interactive Brokers review →
Choose your own venue
Fidelity
Active Trader Pro's Directed Trade ticket sends stock and options orders to the venue you pick. Default routing receives PFOF.
See in comparison table ↑
Automated strategies
TradeStation
Direct routing on TradeStation Desktop for an extra $0.005/share on stocks, so automated strategies can choose the venue. Default routing receives PFOF.
TradeStation review →
See exactly where orders go
TradeZero
Paid Select Routes go straight to NYSE, Nasdaq, NYSE Arca, Cboe BZX and EDGX. Free routes go to wholesalers that pay for the flow.
TradeZero review →
Professional-grade latency
Lightspeed Trading
A long list of selectable exchange routes, with the platform hosted near major exchanges. Per-share pricing makes it a poor fit for casual traders.
See in comparison table ↑
Commission-free apps
Webull, Moomoo
Orders go to wholesalers that pay for them, and neither app advertises venue choice. That's fine for small orders, but check your fills on larger ones.
See in comparison table ↑What Execution Quality Is Worth Per Order
Slippage is the gap between the NBBO midpoint when you submit and the price you actually get. It is charged on every share, just like a per-share commission. The saving from price improvement is highlighted.
| Order size | $0.005 betterPrice improvement | $0.01 worse1¢ slippage | $0.02 worse2¢ slippage | $0.05 worseIlliquid or fast market | $0.005/sharePer-share commission, for scale |
|---|---|---|---|---|---|
| 100 shares | −$0.50 | $1.00 | $2.00 | $5.00 | $0.50 |
| 500 shares | −$2.50 | $5.00 | $10.00 | $25.00 | $2.50 |
| 1,000 shares | −$5.00 | $10.00 | $20.00 | $50.00 | $5.00 |
| 5,000 shares | −$25.00 | $50.00 | $100.00 | $250.00 | $25.00 |
One cent of slippage costs twice as much as a $0.005/share commission. So a “$0 commission” broker with worse fills can cost more than a per-share broker with better ones. Per-share brokers often have a minimum charge per order.
Estimate what fills cost you each month
| Fill quality | Per order | Per month | Per year |
|---|
How execution quality is measured
- Effective spread: 2 × |fill price − NBBO midpoint at submission|. Lower is better. Compare it within the same order-size bucket and the same kind of stock, since large caps and small caps behave very differently.
- Price improvement: the share of orders filled better than the NBBO, and by how much per share. Small per-share amounts add up fast at 50–100 orders a month.
- Fill rate and partial fills: how much of your order fills on the first try. Measure the open (9:30–9:45 ET), midday and the last 30 minutes separately, because partial fills cluster around volatile periods.
- Latency to acknowledgement vs. latency to fill: the broker processes an order in milliseconds, but the fill depends on the venue. Advertised speed figures often cover only the first part.
- Rejections and holds: some brokers hold orders briefly for risk checks before routing them. That delay won't appear in advertised speed but can show up in your fills during fast markets.
The Four Parts of Execution Quality
PFOF or direct
Routing model
Your order either goes to a wholesaler that pays the broker for it, or straight to exchanges. Brokers disclose where orders go every quarter under SEC Rule 606.
vs. the NBBO
Price improvement
Fills better than the national best bid or offer at the moment you submit. This is the part of execution you can measure in dollars.
% filled
Fill rate
How much of your order fills on the first attempt. Partial fills at the open leave the rest chasing a moving price.
Milliseconds
Latency
The time from click to confirmation. It matters for fast strategies, but for most orders a better price outweighs a faster one.
What Advertised Speed Doesn't Show
- Averages hide your order profile. Rule 605 statistics are averaged across order sizes and customers. Excellent averages can mask poor fills on 200-share market orders at the open.
- Internalization on smaller names. Sending all flow to one wholesaler is less competitive for orders above about 500 shares in mid- and small-cap stocks.
- “Smart routing” that isn't. Routing everything to one contracted wholesaler is sometimes marketed as smart order routing. True smart routing compares several venues at once.
- Partial fills in fast markets. Fill rates drop at the open and after news. Ask whether the rest of your order is re-routed or left to chase the price.
- Limit orders behave differently. Brokers route limit orders differently from market orders, so test each type separately.
- Exchange fees on direct access. Direct-access routing can pass through exchange access fees that PFOF brokers absorb.
How To Test Your Broker's Execution
Paper trading can't show slippage, because no real orders reach the market. These steps use public reports and small live trades.
- Read the Rule 606 report. It shows where the broker sends orders and how much it's paid for them. You'll find it on the broker's website.
- Check Rule 605 statistics for your order size. Compare effective spread and price improvement in your size bucket, not the headline average.
- Log 20–50 small live trades. Record the NBBO midpoint when you submit and your fill price. Use the symbols and order sizes you actually trade.
- Test when you actually trade. Compare the open, midday, the close and around news releases separately.
- Test market and limit orders separately. The same broker can handle them very differently.
- Weigh fills against commissions. Convert slippage to a per-share cost, as in the calculator above, and compare it with the commission gap. Repeat the review every month.
How We Compared
Routing facts come from each firm's Q2 2026 SEC Rule 606 report and platform documentation, checked in September 2026 and summarized in the comparison table. Cost examples are simple arithmetic (shares × cents per share) and exclude commissions, exchange fees and market impact on large orders. Brokers marked “Special Offer” are AInvest partners, and AInvest may be compensated when you open an account through this page. Light Horse is affiliated with AInvest. Execution quality changes over time, so check the latest Rule 605 and 606 reports before choosing a broker.
FAQ & Glossary
Which broker has the fastest order execution?
Brokers that let you route orders straight to exchanges give you the most control. Examples are Interactive Brokers (IBKR Pro), Lightspeed, TradeZero's paid Select Routes and TradeStation's direct routing. For most retail orders, price improvement and fill quality matter more than milliseconds: one cent of slippage per share costs twice as much as a $0.005 per-share commission.
Is fastest execution always best for every trader?
No. Long-term investors might prioritize reliability and low costs over intraday execution speed. Active traders benefit most from fast execution during high volatility market hours.
How can I test order execution speed myself?
Place repeated controlled orders using actual capital, log exact timestamps, and compare your filled price to market mid-price and best ask-price at the moment of order submission. Track results across different market conditions.
What affects execution speed most?
Three factors dominate: broker execution model (market maker versus ECN), server location proximity to exchanges (data center), and your own internet connection quality and platform performance.
What is Latency?
The time delay between when you submit an order and when it's executed at the exchange. Measured in milliseconds for active traders. Includes network travel time and broker processing time.
What is Slippage?
The difference between your expected execution price and actual fill price, usually caused by market movement or wide spreads. Can be positive or negative but costs money in aggregate.
What is Bid-Ask Spread?
The difference between the highest buy price (bid) and lowest sell price (ask) for a security. Wider spreads mean higher trading costs and worse execution prices.
What is Smart Order Routing?
Technology that automatically sends your order to the best market venue to minimize execution costs and maximize speed. Evaluates multiple exchanges in real-time.
What is Market Impact?
The effect your order has on market price. Large orders in illiquid symbols cause price movement against you. Brokers managing this reduces your slippage.
What is NBBO (National Best Bid and Offer)?
The highest buy price and lowest sell price available across all market centers at any given moment. Price improvement beats the NBBO.