You set 0.20 lots. The position on the account reads 0.14. Nothing in the channel changed, the signal parsed correctly, the symbol was right. Something between the instruction and the fill reduced it, and the useful reflex is to ask which of a short list of mechanisms it was rather than to assume the copier misbehaved.
Where a smaller size can come from
There are only a few candidates, and they are separable. The order can be filled at less than the requested volume by the broker's server. The size the rule produced can be rounded to the broker's lot step. The size can be reduced or refused because the free margin on the account does not support it. Or the position is smaller because part of it has already been closed at a target, which is not a partial fill at all and is the most common thing people mistake for one.
CopySignals reads back the account and its open positions from the terminal itself rather than assuming the state from what was sent. That design decision exists precisely for this case: a rejection or a reduced fill shows up as what it was, because the reported state comes from the account rather than from optimism about the instruction. The reasoning behind that shape is in running our own terminals.
The minimum lot floor, which is arithmetic and not an opinion
Every broker publishes a minimum volume, commonly 0.01 on a standard retail account, and many publish a step above it. A sizing rule computes whatever it computes, and then reality rounds. Run a small risk percentage on a modest balance against a wide stop and the correct size lands below the minimum. The copier cannot send 0.004 lots. Either it rounds up to the floor, which means the trade carries more risk than the rule specified, or it declines.
Both behaviours are defensible and you should know which one you configured, because the rounding case bites hardest on the widest stopped trades, which are the ones you least wanted to oversize. The full arithmetic, including what happens across accounts of different sizes, sits in scaling lots between accounts.
Split targets meet the same floor sooner
Splitting a position across the levels a channel posted is what most providers assume you are doing, and it is what makes their published results reproducible. It also multiplies the floor problem, because each slice has to clear the minimum on its own.
Splitting 0.03 lots across three take profits gives 0.01 each and works. Splitting 0.02 across three does not. What happens instead depends on the rounding rule rather than on your intention, and the practical result is that a split quietly stops being a split at exactly the account sizes where people are least likely to be watching. Check the size your rule produces before assuming a three way split is running.
A position that shrinks in stages during the day is usually a target being taken, not a fill problem. Partial closes at each level are the copier doing what the channel posted. Look at when the size changed before deciding it was the entry.
Free margin refuses rather than trims
Before an order is sent, a few gates run. One of them asks whether the size the rules produced actually fits the free margin on the account. A trade that does not fit is declined with that reason attached, and the reason is worth reading, because insufficient margin on a correctly sized trade means the account is already carrying more than you thought.
This is where the open position cap earns its place. Three channels reacting to the same release produce three correlated positions, each within its own channel's rules, and the account cap is the only setting that sees all of them. By the fourth, margin is the thing declining trades rather than your risk rule. Which settings sit at the channel level and which at the account level is set out in the settings split.
Netting accounts look like partial fills and are not
MT4 accounts are hedging, so two trades on the same instrument sit beside each other. An MT5 account may be netting, depending on how the broker configured it. On a netting account, a second copied trade in the opposite direction reduces the first rather than opening next to it, so the account shows one smaller position where you expected two.
Nothing was partially filled. Two instructions were both executed and the platform combined them. If you copy two channels that sometimes disagree onto a netting account, this is the normal outcome and it is worth knowing before you set your position cap. The platform differences that show up once trades are running are collected in the MT4 and MT5 notes.
Reviewing a month of sizes
Take the fills that came back smaller and sort them by cause. Rounded to the floor is a sizing rule with no room on that balance. Refused for margin is an account carrying too much at once. Reduced by a netting offset is two channels disagreeing. Reduced by a broker fill is execution, and it is the only one of the four that belongs to the broker.
Only the last category is a reason to talk to your broker. The first three are settings, and each has a specific fix: a different sizing rule, a lower position cap, or accepting that a netting account combines what a hedging account keeps apart. Current product detail is at copysignals.io.
Leveraged trading carries a high risk of loss. A copier enforces the rules it was given on the trades that arrive, and no size that comes back makes a signal a good one.
"Half the size complaints I look at are the broker's minimum lot doing exactly what it says. The other half are a split across three targets that ran out of room at the second one."
— Roman Onta, Executive Director, SINGUARD
Key Takeaways
- A smaller position has four common causes: the lot step floor, a margin refusal, a netting offset, or a target already partially closed.
- The account and its open positions are read back from the terminal, so a reduced fill or a rejection appears as itself rather than being assumed.
- Split targets need each slice to clear the broker's minimum volume, so small positions stop splitting the way you configured.
- On a netting MT5 account, two opposing copied trades combine into one smaller position, which is not a fill problem.
Frequently Asked Questions
Why did my copied trade open at a smaller lot size than the rule specified?
The usual cause is the broker's minimum volume and lot step. A computed size below the floor is either rounded up to it or declined, depending on how the account is configured. Less often the size was reduced or refused because the free margin did not support it, and that refusal is recorded with its reason.
My position got smaller during the session. Was that a partial fill?
Almost certainly not. A position that shrinks in stages is partial closes at the take profit levels the channel posted, which is the split target treatment working as configured. Check the time the size changed against the price action before treating it as an entry problem.
Does splitting across three take profits always work?
Only when each slice clears the broker's minimum volume. Splitting 0.03 lots across three targets gives 0.01 each and is fine. Splitting 0.02 across three is not, and what happens then depends on the rounding rule rather than on the split you asked for.
About the Author
Roman Onta is an Executive Director at SINGUARD. He builds the Prop Firm CRM, the Broker CRM, Scalegram and CopySignals side by side with his brother Alex Onta, and he helped on the design of eTrader, the division Alex built and leads. His ground is worldwide payment processing, AML compliance and the corporate structures brokers are built on, work the two of them carry together, shaped by executive roles in the UAE and international corporates. He lives and works in Dubai for most of the year. Meet the executive duo leading Singuard's five divisions.