A Pegged to Stock order is a buy or a sell order that adjusts the order price by the product of a signed delta (which is entered as an absolute and assumed to be positive for calls, negative for puts) and the change in price of the option's underlying stock price. A buy or sell call order price is determined by adding the delta times a change in an underlying stock price to a specified starting price for the call. To determine the change in price, a stock reference price (NBBO midpoint at the time of the order is assumed if no reference price is entered) is subtracted from the current NBBO midpoint. A stock range may also be entered that cancels an order when reached. The delta times the change in stock price will be rounded to the nearest penny in favor of the order and will be used as your auction improvement amount.