An iceberg seller is where on the sell side, in the orders that...

An iceberg seller is where on the sell side, in the orders that you can see, there is an amount specified to sell say 100,000 shares. If there is an off screen buy for some of these shares, say 50,000, instead of the sell order reducing by 50,000 shares it remains at 100,000. This is the what is meant by iceberg. You can see the top of the sell order but not the full amount that the seller is wanting to dispose of. Often it is instos or financial investment houses that can do these sorts of things, I have seen Perennial Value Management employ this many times, for example. It works the other way as well you can have an iceberg buyer.

In our case, may be it is Acuity Capital being the iceberg seller?

https://www.investopedia.com/terms/i/icebergorder.asp

Off screen sells or buys, where a seller or buyer is not in either the sell depth or buy depth, is not an iceberg order.

Hope this helps, gla.