### Comment:
It means you need margin to sell a 45p, and not be using 4500 in cash to secure it. If MU moves against you with the 45p and you want to take assignment, you will still need to pony up the 4500 in buying power.  
  
  **Margin** made your buying power reduction less.

### REPLY:
You don’t **have** to have $4500, even if MU moves against you. In my example, if MU takes a major dump and ends up at $40, you would need $500 to close it out and avoid assignment. You only *need* $4500 if MU closes at $0.

### END.