Direct answer
When you assess trading signals in forex, you should check the full set of trading costs that can affect the price you actually get versus the price assumed by the signal. The most important categories are: (1) spreads (the bid–ask difference), (2) explicit fees such as commissions, (3) financing costs that apply while positions are held (often described as swap, rollover, or interest), and (4) any additional transaction or account fees that can be triggered by trading activity. Treat these as separate inputs, because spreads and execution timing can change even when the “published” pricing terms look stable.
A key idea is that a trading signal is usually an instruction based on an assumed market price path. Your realized result depends on the costs and the execution environment at the moment the trade is placed and later held.
Mechanism and definition
A spread is the difference between the price you can buy at and the price you can sell at (bid–ask). If a signal references a midpoint or an idealized entry price, a larger spread can make the effective entry worse and the effective exit different from what the signal implies.
A commission is an explicit fee charged per trade or per executed unit, depending on the provider’s pricing model. Even with a “low spread,” a commission-based setup can produce a higher total cost.
Financing/rollover costs are charges (or credits) that accrue when you keep a position open across a time boundary. Signals that assume quick exits may still incur these costs if the trade lasts longer than expected.
To compare signals and providers in a self-contained way, you can separate:
- Published pricing terms (how spreads and commissions are described).
- Variable execution outcomes (what spread you actually faced at entry/exit, and whether your order filled at the expected price).
- Holding-period costs (financing/rollover that depends on time held).
Evidence or example (with assumptions)
Example assumptions (for demonstration only):
- You use a fixed position size.
- You compare two scenarios: one with a “typical” spread and one with a wider spread.
- You hold a trade for different durations.
Step 1: Convert spread into an estimated cost. If a signal implies an entry at a certain reference price but your broker execution includes a bid–ask spread, the effective entry will be offset by roughly half the spread for many practical interpretations (the exact impact depends on direction: buy vs sell).
Step 2: Add explicit fees. If a commission applies per trade, total cost is commission plus spread-related cost.
Step 3: Add holding costs if the trade lasts. Financing costs can dominate short-signal ideas if positions are held longer than intended or if the swap/roll cost structure is unfavorable.
This separation helps you independently explain why two signals with identical “direction” can produce different realized outcomes once spreads, commissions, and financing are accounted for.
Limitations and risks
There are material failure modes that can break any simple cost check:
- Slippage: your order may fill at a different price than the one you expected when the signal was generated.
- Widening spreads: spreads can increase at the time of execution due to liquidity changes, volatility, or market hours.
- Conditional or account-specific charges: some fees can depend on account type, order type, inactivity, or order-routing behavior.
- Model mismatch: a signal may assume ideal fills and ignore time-in-market, so realized costs differ from backtested or illustrative figures.
- Historical vs future: even if spreads and fee levels were stable in the past, that does not establish future behavior.
Because of these risks, do not treat a signal’s implied profitability as reliable without reconciling the costs that would actually apply.
Verification and next question
To verify the relevant facts independently, start by writing down your assumptions: position size, intended entry/exit timing, and whether the plan involves holding across a financing boundary. Then list the cost components you can verify from the provider’s documentation:
- how spreads are described,
- whether there is a commission and how it is calculated,
- what financing/rollover mechanism applies, and
- what other transaction-related fees might occur.