On many days the same brokerage house- CIBC- makes the last sale of the day , always 100 shares, wiping out the bid resulting in the closing bid price being lower than the lowest trade of the day.
As brokerages houses, I believe, value margin accounts on the last bid price (not last sale price), for those who are on margin this steady erosion of value may cause them to have to sell some stock.
Alternatively the traders may see a stop loss order and try to get the stock down to that level.
From my observation of the daily trading over the last period of time there are 3 brokerage houses who seem to be batting stock to and from each other on a consistent basis, always bringing the price steadily down by the end of the day.
I believe this is a concerted effort by either individuals or Institutions to bring the price of Poet down, so that they can pick up cheap stock.
All this is a theory but the pattern now gets repeated daily.
All comments are imho.