Innovation Pharmaceuticals Inc (IPIX)

[I Need Help]

I pretty much agree with your thinking.

One other point: Even though price is always determined at the margin (the price of the last share sold), the size of the trade also is important. The only exception I can think of is if there are no counterbalancing trades. In a normal bid ask situation, if there is 1 Ask for 1,000 shares, it would require 10 Bids for 100 shares to balance the trade (normal Bid and Ask situation). The exception being if there is no liquidity on the counterbalance side, in which case 100 shares could easily cause a gap in price (which is not uncommon for short periods of time). Often times, as the market reacts to the gap, the gap gets filled. This is often the case when the gap is caused by liquidity issues or uncertainty (causing an overreaction).

Just an observation: I notice many 100 share lots traded. Many of these lots are from a larger order being partially filled. Sometimes these orders are filled nearly at the same time, but from different sources. 100 share lots are also common when an order is placed "at the market" and is filled at different price points. I also see many 100 share lots being traded within or outside the spread. Most of these trades are between MM's. No doubt though, 100 share lots can be used to paint a price, or move the price (if the trader has good visibility of the market).