For trading OTC and foreign stocks, in larger volumes, does it make sense to use IB with their per share cost? Or would TD make more sense with low fixed flat fee, anyone know if there is a size limit on it? The OTC are not marginable either so IB's margin rates don't help. Also if there is an OTC ticker with lower volume available, is it worth just trading the OTC ticker instead of the foreign stock to simplify taxes?
Otc isn’t marginable regardless of where you own it. Taxes will be the same likewise. I’d pick whichever broker you think you can get the best, all-in purchase prices or sale price for your trades.