The Execution Model Determines Your Trading Experience
Two brokers can have identical spreads, but if one is ECN and one is STP, their execution will be completely different. This article explains why.
STP Brokers (Straight-Through Processing)
How STP Works:
- You place an order (e.g., buy EUR/USD)
- Broker routes order to liquidity provider (bank, other broker)
- Liquidity provider executes at their price
- Broker passes through price with their markup (spread)
- You see fill at broker's quoted price
Key characteristic: Broker doesn't see your order details; they just pass it through.
Spreads:
- EUR/USD: 1.0-1.5 pips typical
- GBP/USD: 1.2-2.0 pips typical
- Exotics: 3-8 pips (much wider)
Commission: None (cost is in spread)
Slippage: 0-2 pips in normal conditions; 5-20 pips during news events (spreads widen)
Order rejection: Rare (almost never rejected)
Best for: Beginners, swing traders, traders on major pairs
Worst for: Scalpers (spreads too wide), exotic traders
ECN Brokers (Electronic Communication Network)
How ECN Works:
- You place an order (e.g., buy EUR/USD)
- Broker adds your order to an electronic order book
- Your order is matched against other traders or liquidity providers
- You see real-time bid/ask prices from the market
- Your fill is at the best bid/ask available
- Broker charges commission (per lot)
Key characteristic: You see actual market prices; no broker markup.
Spreads:
- EUR/USD: 0.1-0.5 pips typical (raw spread, before commission)
- GBP/USD: 0.2-1.0 pips typical
- Exotics: Still wide (market-dependent)
Commission: $4-$10 per lot (on open AND close = double on round-trip)
Total cost per trade: Spread (0.2 pips) + Commission ($8) ≈ $10 total
Slippage: 0-1 pip in normal conditions; 1-5 pips during news events (minimal widening)
Order rejection: Possible if insufficient liquidity at your price (you're placed in queue)
Best for: Scalpers (tight spreads), high-volume traders, professionals
Worst for: Beginners (complexity), infrequent traders (commission not worth it)
Head-to-Head: Cost Comparison
Scenario: Trade EUR/USD, 1 standard lot (£10,000), 50 trades/year
STP Broker
- Spread: 1.2 pips
- Cost per trade: 1.2 pips × £10,000 = £12
- Annual cost: £12 × 50 = £600
ECN Broker
- Spread: 0.2 pips + $8 commission (open) + $8 (close) = $16 total
- Spread cost: 0.2 pips × £10,000 = £2
- Total per trade: £2 + £12.80 = £14.80
- Annual cost: £14.80 × 50 = £740
Winner: STP by £140/year for low-frequency trader
Scenario 2: High-Frequency Scalper, 1,000 trades/year
STP Broker
- Spread: 1.2 pips
- Cost per trade: £12
- Annual cost: £12 × 1,000 = £12,000
ECN Broker
- Cost per trade: £14.80
- Annual cost: £14.80 × 1,000 = £14,800
Wait, ECN loses? Not if we scale lot size up.
Scenario 2b: ECN with 5 standard lots (professional scalper)
- Spread: 0.2 pips × £50,000 = £10
- Commission: $8 per lot × 5 = $40 per trade ≈ £32
- Cost per trade: £10 + £32 = £42
- Annual cost (1,000 trades): £42,000
Hmm, still expensive. But profit per pip is 5x larger.**
At 5 lot sizes, a 2-pip profit = £100 profit. Commission of £32 is 32% of profit, vs. STP spread costing £60 (60% of profit).
At scale, ECN wins.**
The Hidden Difference: Dealing Desk
STP: Dealing Desk (Broker's Perspective)
- Broker sees your order
- Broker can decide to 'hedge' it (trade against you)
- If you lose, broker profits
- This is a conflict of interest
Example: You buy EUR/USD at 1.0905. The spread is 1.0900/1.0905. The broker keeps the difference (5 pips) IF your order is routed out, but pockets profits if you lose.
ECN: No Dealing Desk
- Your order goes to exchange
- Matched against other traders and liquidity providers
- Broker makes profit from commission, not from your loss
- No conflict of interest
Which is safer for you? ECN theoretically (broker doesn't profit from your loss), but in practice, both STP and ECN brokers are regulated, so dealing desk abuse is illegal.
Execution Quality During Volatility
Normal Market (Quiet Times):
- STP: Spread 1.2 pips, execution instant
- ECN: Spread 0.2 pips, execution instant
- ECN wins on cost
High Volatility (News Events):
- STP: Spread widens to 5-10 pips, execution delayed 100-500ms
- ECN: Spread widens to 2-4 pips, execution 10-50ms
- ECN clearly better (tighter spread, faster execution)
Example: BOE interest rate announcement**
Time: 12:00 GMT (announcement drops)
STP Broker: EUR/GBP spread widens from 2 pips to 15 pips; order execution delayed 200ms
ECN Broker: EUR/GBP spread widens from 0.8 pips to 3 pips; order execution 20ms
If you trade the news event (risky strategy), ECN is vastly superior.
Minimum Deposit Differences
STP Brokers:
- Standard account: £100-£1,000 minimum
- No additional requirements
ECN Brokers:
- Standard account: £5,000-£20,000 minimum
- Higher minimum due to: direct market access, risk management
Impact:** STP more accessible to beginners; ECN excludes small traders.
Negative Balance Protection
STP Brokers:
- FCA-regulated brokers: Provide negative balance protection (you can't lose more than deposit)
ECN Brokers:
- FCA-regulated brokers: Also provide negative balance protection
Both are equally safe from this perspective.**
Decision Framework: STP vs. ECN
Choose STP if:
- ✓ Trading <20 times/month (commission not worth it)
- ✓ You're a beginner (£100-£1,000 capital)
- ✓ You trade major pairs only
- ✓ You don't care about fractional pips
Choose ECN if:
- ✓ Trading >20 times/month (commission pays for itself)
- ✓ You're a scalper or day trader
- ✓ You have £5,000+ capital
- ✓ You want direct market access (transparency)
- ✓ You trade during news events (need tight spreads)
Conclusion: Model Matters Less Than Broker Quality
STP vs ECN matters, but choosing a good STP broker beats choosing a bad ECN broker. Prioritize:
- Regulation (FCA) - non-negotiable
- Execution quality (test with demo) - critical
- Cost for YOUR pattern - important
- Model (STP vs. ECN) - tertiary
Use the decision framework above and you'll find the right fit.