Unfinished auction, explained
An unfinished auction is one of the easiest things to spot on a footprint chart, and one of the most useful. It tells you the market ran out of time, not out of interest — and price often comes back to settle the argument.
What an auction actually is
A market moves by auctioning: price rises until buyers stop finding sellers willing to lift, and falls until sellers stop finding buyers willing to hit. The extremes of a bar are where that process either completed or didn’t.
A finished auction
At the high of a bar, a finished auction prints a zero on the bid. Nobody sold into the bid at that price. Buyers pushed up, found no more offers to lift, and the move simply ended. The same logic inverts at a low: a finished auction there shows a zero on the ask.
The zero is the tell. It means one side of the book went quiet at the extreme — the auction genuinely completed.
An unfinished auction
An unfinished auction (also called unfinished business) is the opposite: at the very top cell, both the bid and the ask printed volume. Buyers were still lifting and sellers were still hitting when the bar closed. The argument never resolved — the bar just ran out of time or volume.
Why it matters
Unfinished levels tend to act as a magnet. Because the auction never completed, there is still resting interest and unsettled business at that price, and markets frequently return to finish what they started. Traders commonly treat unfinished highs and lows as likely revisit targets, and finished extremes as more credible rejections.
This is a tendency, not a rule. It is context, not a signal — it tells you which extremes were resolved and which were not, so you can weigh them accordingly alongside everything else on your chart.
How to spot it on NinjaTrader 8
You need a footprint that shows bid and ask volume separately at every price. Read the top and bottom cell of each bar and ask one question: is there a zero on one side? If yes, the auction finished. If both sides printed, it did not.
Imprint Flow detects and marks unfinished auctions automatically, so you are not squinting at the extreme of every bar looking for a zero.
Imprint Flow surfaces all of this automatically.
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