End-of-Day Holdings and Overnight Inventory Refer to the Closing Position

Summary

The document clarifies terminology for a trading account’s position at the end of a session. It treats overnight inventory, end-of-day holdings, and the end-of-day net position as referring to the inventory remaining at market close and carried into the overnight period. In that practical sense, the terms describe the same account-level position.

It also explains why different labels may appear: inventory can be reconstructed technically from order-book message data, and the terminology may reflect that data-processing context. The answer is a concise definition rather than a method for calculating positions. It does not discuss intraday gross inventory, unsettled trades, market-specific closing conventions, or accounting treatments that could affect how a particular system reports holdings.

Key ideas

• Overnight inventory generally refers to the position held when the market closes.
• End-of-day holdings and end-of-day net position are used as equivalent terms in the described context.
• Terminology can vary with the technical method used to reconstruct inventory from order-book messages.
• The answer does not specify special accounting or market-close conventions.

Tags

# End-of-day holdings vs overnight inventory


# End-of-day holdings vs overnight inventory












I am wondering whether these two terms identify the same thing:

- overnight inventory

- end-of-day holdings

The way I would explain it intuitively, the inventory that is held overnight should be identical to the holdings at the end of the day, for an individual trading account.

If that is correct, I wonder whether, by extension, end-of-day net holdings could be referred to as net overnight inventory.

## Answer by altabq (score 1)

https://quant.stackexchange.com/a/15046

It appears that these are actually all the same thing.

overnight inventory, end-of-day holdings, end-of-day net position, it all identifies the same thing. The different terminology arises from how, technically, an account's inventory is reconstructed using order book message data. However, they all identify the inventory at market close, i.e. the overnight inventory.

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.