On very rare occasions, to preserve market integrity, we might need to annul trades that are erroneous or were done on account of fraud or market manipulation. Very rarely, some fills might get executed at prices very far from prevailing market price. If there is a huge difference in the fills from the prevailing price and if the orders, which end up taking poor fills, were not intentional limit orders, we reserve the right to annul those fills by generating counter fills that will reduce the profit generated from any such fills to zero. This is done to deter participants from placing limit orders deep in books at prices which are very far from the prevailing price. This helps parties who were at losing end and who chose not to accept such fills but still received them because of some market or other order which got executed in an illiquid order-book.