POET Technologies Inc.

Newbie question

Could someone please try and explain to me why the price such as yesterday for example dropped 2 cents after trading was complete. And why does it always drop instead of going up.

Do traders wait till closing time to submit a low bid to catch it after the trading day is complete?

sorry if this is a stupid question , but I am curious.

BTW I decided to put my best friends photo up also. She was17 years old when we had to put her down because of pain in her hips