The open gets two reads and is a far smaller auction. On 9 November 2026 the NYSE total read 94M to buy at 9:28:05 ET and 98M to buy at 9:29:40, 6% of 1.74B paired. Paired volume at the close was about 20 times larger.

In the Helious terminal as a strip above the news feed, as a card on the feed, on the squawk, at /v1/imbalance and /v1/imbalance/{symbol}, and through the get_market_imbalance MCP tool. Pro and Ultimate see each read live. On Free each read opens when its auction prints, at 9:30 ET and 4:00 PM ET.

Market on Close Imbalance: How to Read It

Q: What is a market on close imbalance?

The orders left over in the closing auction after buys and sells have been paired. A buy imbalance means the auction needs sellers to step in, so the closing print tends to land above the pre-auction price. A sell imbalance is the mirror image.

Q: How does Helious calculate it?

Helious calculates it from every listing's own auction print. It multiplies each NYSE listing's unpaired shares by the stock's previous close and sums buys less sells, for every NYSE listed company (about 2,400 names) and for the S&P names listed on the NYSE (343 of 502).

Q: What did a real close look like?

On 9 November 2026 the NYSE total read 684M to buy at 3:50:10 ET, 1.12B to buy at 3:55:10 and 131M to buy at 3:58:30, while paired volume rose from 28.32B to 35.43B. The lean fell 88% in the last 3 minutes 20 seconds.

Q: What does the Helious read add?

A few plain sentences with each read: how big the lean is against paired volume, how it moved since the previous read, whether the S&P names agree, and what that usually means for the print. It is not a trade call.

Q: When do the reads land?

Two for the open, at 9:28:05 and 9:29:40 ET, and three for the close, at 3:50:10, 3:55:10 and 3:58:30 PM ET. On a 1pm early close the close reads move three hours earlier, and on an exchange holiday there are none.

Helious Desk · 9 November 2026 · 5 min read

In the last minutes before the 4:00 bell, the NYSE shows how many shares in each stock still have no match in the closing auction. Helious adds those up into one number: net dollars left to buy or to sell. On Monday 9 November that number read 1.1 billion to buy at 3:55 PM ET, and 131 million to buy three minutes later. Here is how to read it, using that day's real reads.

1. What is a market on close imbalance?

Orders to trade at the closing price gather in the closing auction. The buys and sells that match each other are paired. What is left over is the imbalance. A buy imbalance means more shares want to buy at the close than to sell, so the auction needs sellers to step in, and the closing print tends to land above the pre-auction price. A sell imbalance is the mirror image. The opening auction works the same way, and there the imbalance sets the direction of the opening cross.

2. How does Helious calculate it?

Helious calculates the figure itself, from every listing's own auction print. Going into each auction, the exchange publishes each NYSE listing's unpaired shares and the side they sit on. Helious multiplies those shares by the stock's previous close, then sums buys less sells. The previous close gives every stock one fixed price, known before the read starts.

There are two baskets. NYSE MARKET sums every NYSE listed company, about 2,400 names, with ETFs and preferred shares left out. S&P 500 sums the S&P names listed on the NYSE, 343 of the 502 members on Monday. Each figure is called small, moderate or large. The NYSE total is small up to 750 million and large above 2.5 billion. The S&P figure is small up to 500 million and large above 2 billion.

3. What did a real close look like?

These are the three close reads from Monday 9 November, all to buy:

Read (ET)	NYSE net	Share of paired	NYSE paired	S&P names net
3:50:10	684M	2%	28.32B	846M
3:55:10	1.12B	4%	30.54B	1.35B
3:58:30	131M	under 1%	35.43B	451M

The change matters more than any single read. In the 3 minutes 20 seconds after 3:55:10, the NYSE lean fell 88% while paired volume rose by 4.9 billion. That is what offsetting orders look like when they arrive and match off a lean. A trader who saw only the 3:55 figure would have been leaning on a number that had mostly gone by 3:58.

Two more things sit behind the final read. The S&P figure was larger than the NYSE total because S&P names are only part of the NYSE: the listings outside the basket summed to about 320 million to sell. And a small net can hide large two-way flow. The final NYSE read was 2.91 billion to buy against 2.78 billion to sell. LLY (256 million) and BRK.B (235 million) to buy came to nearly four times the whole net, with TSM (177 million) and JPM (162 million) the largest to sell.

4. What about the open?

The open gets two reads, and it is a far smaller auction. At 9:28:05 Monday's NYSE total read 94 million to buy, with S&P names 99 million to buy. At 9:29:40 it read 98 million to buy, 6% of 1.74 billion paired, with S&P names 63 million to buy. Paired volume at the close was about 20 times larger. The largest names at the open were TSM, GEV and RYAN to buy, and V, CLS and XOM to sell. TSM went from 20 million to buy at the open to 177 million to sell at the close.

5. What does the Helious read add?

Every read comes with a few plain sentences: how big the lean is against paired volume, how it moved since the previous read, whether the S&P names agree, and what that usually means for the print. Monday's final close read said:

On Helious, we are seeing this as a small buy lean into the close: 131M to buy, under 1% of paired. Down from 1.1B at 3:55: the pressure is easing. S&P names agree: 451M to buy. Expect support into 4:00 and a close above the 3:50 price. Some can give back after the bell. At this size it often fades.

Treat it as a description of what an auction of that size usually does. It is not a trade call, and it is written before the print, so it can be wrong.

6. When do the reads land?

Two for the open, at 9:28:05 and 9:29:40 ET. Three for the close, at 3:50:10, 3:55:10 and 3:58:30 PM ET. On a 1pm early close the close reads move three hours earlier, and on an exchange holiday there are none. In the terminal the strip above the news feed appears two minutes before each auction's first read with a countdown, and goes away ten minutes after its last read. The rest of the day it is not on screen.

7. Where can I see it?

In the terminal, as the strip with two circles and the Helious read, plus one card per auction on the feed and a line on the squawk at each read. Every read is stored and served at /v1/imbalance, one stock's prints are at /v1/imbalance/{symbol}, and AI clients can call the get_market_imbalance tool over MCP. Pro and Ultimate see each read the second it lands. On the Free plan each read opens when its auction prints, at 9:30 ET for the open and 4:00 PM ET for the close. The help article has the full detail.

8. What does it not cover?

NYSE main-board listings only. Nasdaq listings and NYSE Arca listings are not on this feed. That leaves out the Nasdaq-listed mega caps, QQQ and SPY, and it is why 159 of the 502 S&P members are missing from the S&P basket. Read that figure as the NYSE part of the index, not the whole of it.