Someone really doesn't want Bitcoin to go down, huh?
Look back in this thread for when I posted when those staggered bids were first added. She's been waiting patiently for the "market" to drop for quite a while and I guess her patience is running out. I don't think she is trying to keep the "market up", I believe she's an actual buyer.
She is playing with a rather large ball of capital at what I would consider a very risky time. I also notice that these Bids are getting pulled outwith 'her' office hours. Although, from experience, the walls on Stamp are more likely than not to be genuine, as opposed to on Bitfinex, where 9/10 times, anything large and imposing is generally intended to trick traders into doing the wrong thing.