Extenders

The basic options package provides you with a feature called quote code extenders. Basically, extenders are quote code prefixes (because you put them at the beginning of a quote code). In options, there is a relationship between an underlying instrument, and option calls and puts. Extenders enable you to specify a value from any instrument in this relationship.

In options, quote codes written with extenders display a variety of values, depending on the symbol you enter. The following table summarizes the performance of option quote code extenders.

If symbol in $1 is	$1.U.<code> displays	$1.C.<code> displays	$1.P.<code> displays
underlying	underlying	at-the-money call	at-the-money put
call	call underlying	call	put with strike & expire equal to $1
put	put underlying	call with strike & expire equal to $1	put

Extenders are particularly useful in formulas. You can use extenders to write formulas that use call, put, and underlying prices. Your Aspen Options package comes with a formula that illustrates this application:

Where:

CONV = formula name.

$1.C.RECENT = recent price of call.

$1.P.RECENT = recent price of put.

$1.U.RECENT = recent price of underlying.

$1.C.STRIKE = call strike.

This formula requires only one instrument as an argument, but, internally, it uses prices from three different instruments to define the arbitrage relationship between a call and a put at a particular strike and expiration. The conversion formula (CONV) uses quote code extenders. Take, for example, the first element in the conversion formula:

$1.C.RECENT

This code instructs the formula to get the recent price of a call. In context of formulas, the instrument is passed to the formula as an argument. For more information on passing arguments to formulas, click here.

Underlying Instruments

The U. extender makes any code display information on the underlying instrument. To use the U. extender requires the following syntax:

$<number>.U.<code>

Example:

$1.U.MID

Calls

The C. extender makes any code display information on an option call. The C. extender requires the following syntax:

$<number>.C.<code>

Example:

$1.C.BID.

Puts

The P. extender makes any code display information on an option put. The P. extender requires the following syntax:

$<number>.P.<code>

Example:

$1.P.ASK.