Price movements after market close

Why does this happen?
Who purchase or sells these shares after market close?
Do these movements provide indication of a trend for opening the next day? i.e. if 4pm close is $10.00 then at 4:10 the price increases to $10.00 - would this influence an upward trend the following morning barring any adverse news in the mean time?

it is similar to when the market is in pre-open before trading begins. it is like the pre-open auction but just at the end of trade.

im not sure of the time frame that it runs for but it seems to be around 5 - 10 mins after close.

it is some sort of indicator of how much demand a stock has right on close. you can see this by how much a stock is been bought up after close and whether it closes on high for the day.

also the opposite is true if people want out they will dump a stock all day and then a lot may also dump on the ending auction for the day after close bringing the closing price down.