Buying ahead of material information, IMO. All companies have a grace period when insiders can buy stock on the open market. It is possible those large buys were from insiders buying prior to a quiet period where they are not allowed to add to their positions. Some companies allow buying and selling 2 weeks to a month before and after material events. Will be watching closely.
DHSM - reason1, looks like there are more and more market makers starting to show up on level 2's. This is a good sign. Looks like there may be some speculative buying and selling. Will create liquidity for those looking to buy low and sell high. Will be watching closely as new market makers continue to line up.