What is a Market On Close Imbalance?:
Each trading day the major exchanges have to close and set a closing price. The NYSE uses the market on close orders to do that, the Nasdaq uses a crossing mechanism. These orders need to be entered before 15:50 ET after which they cannot be cancelled. A market on close imbalance occurs a larger number of market on close orders on the buy or sell side. If a trader wants to execute a MOC past the 15:50 deadline they must enter an order opposite the imbalance. For instance, if stock A has a buy imbalance then only a sell MOC will be accepted.
For traders closing around the close, the Market Imbalance Meter (MiM) blends both the Nasdaq cross and NYSE market on close imbalance data. The MiM aggregates and produces a unique view for traders. Closing price action begins at 14:00 until the 16:00 cash close. Trades should keep the Final-2 hours in mind while trading.
May 12, 2021 Data:

The arrows show the time and price of buy and sell program trades going into the closing hours of the market on close trades. To understand more about them, read the daily SpyGate post.
Imbalance

The early MiM had was showing a decent buy imbalance. That flipped just before the reveal to an almost $2B sell. The MiM did not get a data refresh in time. Unlike the past two days, the Dquotes were in line. This is a streak of selling MOCs into the end of the day. A bearish signal.
Symbols

Leading the symbols on the buy-side were BABA with $348M to buy and GOOGL with $101B to buy, while AAPL and MSFT led the sell-side with $200M and $149M respectively.
Sectors

The only positive sector was Consumer Cyclical. Utilities had a decent selling lean.
Check out our daily SpyGate post on other trades during the day.
If you are interested in joining our trading community and gaining access to our opening and closing data as well as our developing tape sniffing products, head here: https://mrtopstep.com/l/mim
Don’t trade the market cash Open and Close without some type of insight. At least understand what is mechanically happening at 8:00 to 9:30 am ET and 14:00 to 16:15. These are very volatile trading windows. See you in the room.
Marlin