A Market Order Can Become Several Deals

One market order does not always equal one fill. A platform may execute the requested volume through several deals at different prices, leaving the trader with a volume-weighted average that differs from any single print on the chart.

MetaTrader's official model is useful here: an order is the instruction, a deal is an executed transaction, and a position is the resulting market exposure. Depending on the venue and fill policy, an order can be filled completely, partially filled, rejected or completed through multiple deals.

Rebuild the actual entry

Imagine a buy order for 100,000 units filled as follows:

The volume-weighted average is 1.160205, before fees. Simply recording the first fill at 1.1600 understates the entry cost. If only 75,000 units filled, the remaining exposure also differs from the original trading plan.

Partial execution is not automatically misconduct. It can reflect the available liquidity, execution venue and fill policy. The correct question is whether the treatment matched the disclosed rules. MetaTrader describes fill-or-kill, immediate-or-cancel and return-style policies, but the modes available depend on the symbol and broker.

This issue becomes more visible when markets jump. August U.S. CPI rose 0.4% month on month, and the Fed meets on September 15–16. A news release can cause available prices to change faster than a large instruction is completed. Scaling volume down may reduce market impact for some orders, but no generic threshold guarantees a single fill.

This recent MT5 order tutorial shows the interface for sending orders. After execution, the authoritative evidence is the account's order-and-deal export, not the ticket window alone.

The complete post-trade process is therefore: group all deals by parent order, sum filled volume, calculate the weighted average, add commissions, and compare the result with the strategy's maximum acceptable entry. If the remainder is unfilled, decide deliberately whether to cancel or resubmit. One click may create several economic decisions.

Sources

• MetaTrader 5: general trading concepts
• MetaTrader 5: performing deals and fill policies
• BLS: August 2026 CPI
• BLS on X: official discovery feed
• Federal Reserve: September meeting calendar

The numerical example is illustrative; actual fill policies and price precision vary by venue.