Why it matters
IOC reduces ‘hanging order’ risk. It lets you take liquidity now without leaving the remainder exposed to later regime changes.
Decision use: treat this term as a risk input. If you can’t observe it, you can’t size for it.
Common trap
Assuming IOC means full fill. IOC often results in partial fills, which can leave you with an unintended position size if you don’t reconcile.
Example
You send IOC for 10 units; 6 fill, 4 cancel. If your system assumes 10, your hedges and stops are now wrong.
Operational cue: if you can’t point to it on the chart, in the DOM, or in your broker logs, treat it as a story and trade smaller.
Notes
Quick rule
- If you see this repeatedly, you are in a different regime than your model assumes.
- Regime change usually means position size change.
- When in doubt: trade smaller, or don’t trade.