sell order not going to prevent your broker from utilizing up to 140% of your margin debit balance, should it be equitable to do so.
brokers, by rule, can do whatever they want with up to
140% of your debit balance.
so, no matter what method, transaction, or series of transactions a trader finds their way into a debit balance, the broker can utilize up to 140% of portfolio securities to loan (pledge, hypothecate, re-hypothecate)
gtc orders have 0 impact on this.
generally, for reg-t margin, a short sale requires 30% of the collateral/margin requirement to maintain the short position.
if we go back to scenario of 50k cash used to buy 50k of stock, under reg-t i’ll have about 100k worth of buying power still.
i can use that to short another security. but i’ll need to maintain 30% of the total value of short in my remaining buying power. so i should be able to short about 35k worth of stk B
as soon as stock a goes down or stk b goes up, my maintenance requirement will increase and i’ll either be liquidated or margin called, depending on broker
the GTC thing is meaningless at IB. they don’t prevent the broker from loaning my shares, or liquidating any positions.
they cancel gtcs automatically when a security goes through a corporate action, or position transfer, etc.
the only way a broker can touch your shares is if you enter into margin debit or opt into fully paid lending.
if you enter into margin debit, they can utilize up to 140% value of that margin debit.
