Margin Q????

I need some clarification on the calculation of margin interest. I understand that if I were to have a hypothethical portfolio of $10,000 and I bought $15,000 dollars worth of stock I would be charged interest on the $5,000 dollars borrowed to buy stock. My question is how this works on the short side. If I had the same $10,000 dollar portfolio and and bought $10,000 dollars of stock and SHORTED $5,000 dollars in stock would I be charged margin interest on the $5,000 worth of shorts? Is there a difference?

 

you are not charged interest on the short position because it is a credit balance.

 

Thanks. MB Trading is telling me different. They told me it does not matter, the interest is calculated the same.

 

Yea I just looked up IB's and they charge for credit and debit cash balances too but the rate is 2 points less.

 

anybody else. According to my monthly statement I actually got paid interest on the profit I made on my shorts. This is not consistent with what MB is telling me.