Getting cold feet, page-94

Very large sell orders placed a little above the current price. They're intended to make people think that if they want to sell they should place their order below the price of the big order. That ensures a steady supply of shares below the blocking order for somebody wanting to accumulate at the current level. If the lines below the blocker get wiped the blocker will be cancelled.

Of course, they might not be blockers... they could just be large sell orders!