Apple' share price is increasing but several institutional investors are not able to purchase all the shares they desire

[answerhappygod]

Apple' share price is increasing but several institutional
investors are not able to purchase all the shares they desire at
that time. Is there a legitimate argument that the DMM is holding
back the shares to secure higher profits?
Yes - DMM's must provide liquidity to ensure buyers and sellers
always have transparent price discovery and full execution in any
type of market in the securities that they specialize in to be
fully efficient market makers.
No - if both sides of the market are satisfied that quotes are
competitive, orders must be taken but size can be adjusted
accordingly based on DMM inventory.