Why is the threshold for doing OTC so high? Because of bank limits, risk control, etc. Been doing OTC for 7 years, using the same card for 7 years, never frozen or restricted—got my own strict set of standards. (Also, for large transactions, bosses usually book in advance. Otherwise, I can only take as much as I have. For example, if you want to sell 500 but I only have 300, you'll have to wait until tomorrow!)