To revise, add, or delete a strategy, click the strats speed button, then choose Edit strategies from the program's main menu. (This menu choice appears only when the strats window is displayed.)

Click any combination listed in the box at left to see its details. The description lines are free-form but must conform to the required syntax.

This line consists of three items. The strategy name comes first; it must be a quoted string. Use the double-quote, not the single-quote key on your keyboard.

A strategy consists of two assets "A" and "B". This line
must specify the type of each asset in the form illustrated above, A=*type**
*and B=*type* where *type*
can be call, put,
underlying or none.

For a single-asset strategy (buying calls or writing puts), specify A as the appropriate asset type. You can then leave off the B= clause, or enter B=none to get the same effect.

The rule line is a logical expression (a predicate) that determines whether a particular combination is selected.

For instance a "calendar spread" is typically set up by purchasing calls that expire far in the future, and simultaneously selling calls having the same strike price but which will expire before the ones you bought. The rule illustrated above (a.life<b.life) and (a.strike=b.strike) captures this specification.

The rule syntax allows any logical combination (and, or, not) of arithmetic comparisons. The values that may be compared are:

- a.life or b.life the remaining lifetime of option A or B.
- life the remaining life of
the first option to expire,
*i.e.*min(a.life,b.life) - a.strike or b.strike the strike price of either option.
- u.price the current price of the underlying stock or index.
- u.bar(
*z,d*) the stock price that is*z*standard deviations from the current price after*d*days, given the stock's assumed volatility. This test requires that*z*falls between -3.0 and +3.0 standard deviations. - a.fair or b.fair the fair value of the option when priced by the settings in the Environment panel
- a.delta or b.delta the delta of the option when priced by the settings in the Environment panel
- a.bid or b.bid the quoted bid price of the option
- a.ask or b.ask the quoted ask price of the option
- min(
*x,y*) the lesser of*x*and*y* - max(
*x,y*) the greater of*x*and*y* - abs(
*x*) the absolute vaue of*x* - any arithmetic expression involving combinations of these, and constants.

- (a.strike/u.price) > 1.15 the strike price of option A must be at least 15% higher than the current strike price.
- a.life > 180 the remaining life of option A must be at least 180 days.
- (a.fair - a.ask) > 0.50 the fair value is at least 50 cents more than the asking price.
- a.strike < u.bar(-1.0,life) the
strike of option A is below the -1.0 standard deviation price movement
boundary after
*life*days (in other words, it strikes below the -1.0 sigma bar at expiration).

Arithmetic expressions can use the operators *, /, + and - to denote multiplication, division, addition and subtraction. The relational operators are the familiar ones: <, <=, =, <>, >= and > .

It's best to use parentheses liberally when writing rules. For the computer
scientists among you, the expression grammar sets operator precedence in
increasing order as: or, and, relational operators, add/subtract,
multiply/divide, and the unary leading operators (not, minus sign, plus sign). Therefore

a.strike>=u.price
and a.life < 90 is a valid expression that
means (a.strike>=u.price) and (a.life
< 90) .

For each combination that passes the rule, a line the strategy table will be generate with the assets A and B in some ratio. The ratios are listed as illustrated, separated by commas. If the asset is an option, its ratio number is the number of contracts. If it is a stock or index, the ratio is the number of shares or units. So a covered call might have ratios -1/100, -5,500 meaning two setups: short one contract and long 100 shares; or short 5 contracts and long 500 shares.

For a single-asset strategy, it is acceptable to list single numbers separated by commas. Thus 1, 5 would mean either 1 or 5 contracts of an option. You can alternatively enter ratios in the form 1/0, 5/0 and so forth.

The Clear button erases the current Strategy, Rule and Ratio lines without changing the actual list of defined strategies. The Add or replace strategy button replaces the named strategy if it exists; or add a new strategy if no strategy with that name exists. Click Delete to remove the strategy selected in the strategy list at the left side of the window.

After altering or adding strategies, you must click the Save changes button to make them permanent. Otherwise they will be lost. Of course you can make several changes, and only save them once after you're done.