Buy Vs Sell, page-6

If there is no news, it is normally a temporary thing - typically caused by someone wanting to take a decent position in a hurry and therefore the sellers not having an opportunity to provide further liquidity. What also normally happens is some sellers use the opportunity of the fast uprise in the SP to take some profit off the table while they can (often called nervous nellies).

If the company has some real good stuff ahead of it, then a lot of sellers will not be in a hurry to re-populate the sell side and that puts the SP under some good upward pressure....obviously a good sign. Hope that helps.