SEBASS
As I see it, MMs acumulate during PPs walk down and sell for higher profit margins when PPs runs up.
They maintain an inventory, if they can slowly walk PPs down, buying some each day, they average down their holdings. Thus when something good happens to the company, which creates demand,and the PPs shoots up so fast they lose control of momentium, the increased profits between their buy price and their sell price, helps their bottom line after the run.
Lets say MM X holds 500k @ .10 and during a slow volume period the PPs goes down to .08. At the end they bought another 500k at prices from .10 to .08 and their new inventory is now 1 mil at .09.
Now the stock runs to .20, they sell 1 mil on the way up, which they own at .09. The inventory profit now incresed by 1 cent per share sold. Plus they still make a precentage fee on each share they moved. Increased profits, increased fees.
As you can see, it is in the MMs best interest to maintain a steady volume, while things are quite, so they can accumulate lower, while maintaining fees that keep their business in the green. This is all good business. The bad part is the tricks they use to get what they want.