Why Follower Fills Differ from the Source

A copied trade rarely fills at the exact price the source got — and that's normal, not a bug. A trade copier sends the order; each follower's broker decides the price it actually fills at. Knowing why the two differ — and what a copier can and can't control — sets the right expectation before you copy across accounts.

The follower's broker sets the price

A copied order is filled by the follower's own broker, at its available price, against its liquidity, in its book. When the source opens a position, the copier dispatches a matching order to each follower, and from there it's out of the copier's hands. Two brokers quoting the "same" instrument at the same instant can still print slightly different prices.

What causes the difference

Four things move a follower's fill away from the source's: spread, latency, requotes and fast markets.

• Spread — each broker has its own bid/ask, so the entry and exit differ.
• Latency — the milliseconds to dispatch the order plus the broker's own execution time mean the market can move a touch before the fill.
• Requotes / rejections — some brokers requote in fast conditions rather than fill at the asked price.
• Fast markets & slippage — around news or gaps, the available price can be away from the source's by the time the follower fills.

Partial fills and fast round-trips

On very quick trades a follower may open and close almost back-to-back, or — if the follower's broker is momentarily unreachable — a fill may not land at all. A good copier surfaces any not-copied order with a reason, and tells you when a follower missed a close while it was offline, so a missed fill is visible rather than silent.

What a copier controls — and what it can't

A copier controls how fast the order is sent: dispatching over real-time streams the moment the source fills is faster than polling on a timer. It does not control the broker's price, spread or execution. So a faster copier narrows the time window — it doesn't guarantee a matching price. No honest copier promises identical fills, and any tool that claims to is overselling.

Where Trepeat fits

Trepeat dispatches fills over persistent real-time streaming connections (event-driven, not timer-polled), so the order goes out the moment the source fills — then each follower's broker sets the final price. Failed and skipped copies show on the Trades page with the reason, and raise an alert. Fills outside the allowlist, before Run, or missed while a connection was down are not recorded. If a follower was unreachable when its source closed, Trepeat alerts you on reconnect so you can close that copy. It repeats your trades quickly and honestly; it can't override a broker's execution. See the scalping trade copier for the speed angle and what a trade copier is for the basics.