Partial order fills and multiple parcel execution

Why Was My Order Only Partially Filled or Split into Multiple Parcels?

When placing an order, especially for a larger number of shares, you might notice that only part of it is filled or that it fills in multiple parts. This is completely normal and is known as a partial fill or receiving multiple parcels.

What is a Partial Fill?

A partial fill happens when only part of your order is executed - usually because there weren’t enough shares available at your chosen price.

If your limit price is reached but not enough volume is available, only some shares may be matched.

If the rest of your order isn’t filled before expiry (or you cancel it), it won’t be executed.

You’ll keep any shares that were filled.

Example:

You place an order to buy 100 shares. 30 shares are filled before you cancel it:

• 10 shares at $1.00

• 10 shares at $1.25

• 10 shares at $1.50

You’ll get three separate trade confirmations, and your average buy price will show as $1.25.

Why Does My Order Get Split into Parcels?

Orders are matched based on Price-Time Priority and Market Depth:

Price-Time Priority: Orders with better prices and earlier timing are filled first.

Market Depth: There may not be enough shares available at a single price to fill your order all at once.

Example:
You place a buy order for 1,000 shares. The exchange finds:

• 200 shares at $10.00

• 500 shares at $10.01

• 300 shares at $10.02

This leads to your order being matched against multiple smaller orders in the market, resulting in separate parcels at different prices.

How do partial fills affect your price?

Limit Orders:

• All parcels are filled at your limit price or better.

• You’ll get an average price that’s equal to or lower than your limit.

• You might only get a partial fill if the market moves away from your price.

Market Orders:

• Your order is filled at the best available prices, moving through the order book.

• This can lead to slippage, where your average price is worse than the price you saw when placing the order.

• The bigger your order and the less liquid the stock, the more slippage you might see.

Important: You’re only charged one brokerage fee per order, even if it’s filled in multiple parts.