last minute buyer

I'm pretty sure I'm the only person holding this stock on the asx, but has any one else noticed for the last 5 trading days a buyer comes in and closes the stock on even money or higher ?

You can nearly set your watch by it.
In the last 15 minutes he places one or two small bids just below the offer, and then hits the offer right on closing.
Any left over bids usually disappears the next morning, and he returns in the afternoon to repeat his task.

I thought I was imagining things until I saw it again today.