Combo Orders

ScaleTrader supports guaranteed combination orders. When using ScaleTrader for creating generic combination orders, note the following:

Scale combos can only be sent as Limit orders.
When you create a STK STK generic combo, the ratios are automatically simplified when you save the combo. This means that the combo you define in the Combo Selection box to Buy 300 XYZ and sell 700 ABC ends up on the ticker line as Buy 3 XYZ and Sell 7 ABC.
Scale parameters such as Total Order Size and Initial and Subsequent Component sizes are expressed in terms of the total combo. For example, if you buy a generic STK STKcombo defined as Buy 10 DELL, Sell 1 IBM , and set the Initial Component Size to 5, the first component order would be: Buy (5 x 10) DELL, Sell (5 x 1) IBM.
Price fields, including the Starting Price,

Use ScaleTrader for combination orders

Non-guaranteed combos are not supported in ScaleTrader.

Create a combination market data line on the trading screen:

In a blank line, type an underlying symbol and hit Enter.

Choose Combinations, then select Option Combos.

Choose a destination, and use the ComboTrader Combo Selection box to define a strategy. Click OK.

In the combo line on the trading screen, click the Ask Price to create a BUY order; click the Bid Price to create a Sell order.
In the Type field select LMT. Only Limit orders are supported for Scale combos.
Set the time in force to DAY or GTC.
Set the scale attributes:

Scale Init. - (Initial Component Size) This value defines the size of the first, or initial, order component. For combination orders, the size parameters are expressed in terms of the combo, for example, if the spread is defined as buy 2 IBM, sell 3 MSFT, the Initial Component Size of 10 would result in buying 20 IBM (10*2) and selling 30 MSFT (10*3).

Scale Sub - (Subsequent Component Size) Optional field used in conjunction with the Scale Init field, this value defines the order size of the subsequent scale order components. If left blank, all order components will be sized based on the Scale Init value. For combination orders, this value is in terms of the combo, see Scale Init above.

Scale Incr. - (Price Increment) This amount is used to calculate the per-unit price of each component in the scale ladder. For a combination order, the pre-unit price is the combined price of all legs in the combo, for example, buying IBM at $15.00 and selling MSFT at $6.00 would yield a combined price of (2*$15.00) - (3*$6.00) = $12.00. Note that the price increment cannot be negative.

Scale Profit Offset - A value in this field instructs TWS to submit profit-taking orders, and defines the minimum amount of profitability you will accept to exit a position. ScaleTrader will submit an opposite-side profit order against the original order, using the limit price of the parent component plus/minus the profit offset. For example, if you submit a 10 contract BUY limit order at $12.00, with a component size of 2 and enter $1.00 as the Scale Profit Offset, as soon as the first component executes, TWSwill submit a 2 contract SELL limit order at $13.00. Use the Scale tab on the Order Ticket to set advanced profit order instructions.

If necessary, modify the Lmt Price which is used as the starting price for the series of order components. Note that for combination orders, the price represents the combined price of all legs in the combo, for example, buying IBM at $15.00 and selling MSFT at $6.00 would yield a combined price of (2*$15.00) - (3*$6.00) = $12.00.
Transmit the order.

You can monitor the progress of your scale orders by right-clicking on the order line and selecting View Scale Progress.

For more information on scale orders, visit the Order Types information page.