XPE Charts, page-1464

It's a risky strategy but many retailers (ie us) still rely solely on depth as a technical indicator for SP movements. Depth can be manipulated very easily. If you have enough money, or enough shares you stack the buy side with "fake" bids just a touch away from the current SP, or in this case place a huge sell (or lots of small ones) on the ask side, making it look like there is selling pressure. They'll disappear as the SP approaches. There's no one way of spotting it, you really need live data to see it happening. Here's some homework, an example of propping (the opposite of capping). Go have a look at PIO's depth currently.... What do you see that's interesting?