I'm no expert but I've always thought that these small,...

I'm no expert but I've always thought that these small, odd-looking, trades (which seem to appear in just about all non-small-cap stocks) are due to algorithmic trading implemented in a trading program (A.K.A. bot). My guess is that these small trades are either probing or nudging/testing the market to prompt a response from other traders - be they human or computer. They also seem to be intended to attempt to cheaply maintain a particular share price for some purpose. It's basically stimulating the market to see what happens and then react or just outright direct the share price.

Hence, it's likely institutional or 'sophisticated' traders. Obviously they don't pay brokerage on trades in the same manor as a retail investor considers brokerage.

Someone who knows more please enlighten us.