I too have a Margin acct. I think he means buying on margin. I do not know if you can or cannot. But I do know that having a margin acct and buying on margin are two different things
But u buy the pennies w cash not on margin. A stock is not marginable unless it is over $4 usually. When the broker calculates your margin buying power they don't include penny stocks in the calculation. I also have a margin acct and penny stocks in that acct. just can't buy pennies using margin as that is borrowed money.