The ForwardStart function calculates the theoretical price, sensitivities and the implied volatility value of a European style forward start option using Rubinstein’s model. See Multiple Exercise Options for a further explanation.
ForwardStart |
(OptionType, ModelStatistic, Asset, TimeStart, TimeExpire, Volatility, InterestRate, YieldRate, Alpha, MarketPrice, TimeFormat, InterestType, YieldType) |
Note: Optional arguments are shown in Italics. MarketPrice is not Optional for the Implied Calculation.
Argument |
Description |
OptionType |
Alphanumeric value indicating the type of option: •Call = 1 or "c" (case insensitive) •Put = 2 or "p" (case insensitive) |
ModelStatistic |
Numeric value indicating the type of function required for the return value: •Theoretical = 1 •Delta = 2 •Gamma = 3 •Theta = 4 •ImpliedVol = 5 •Vega = 6 •Rho = 7 •Psi = 8 •Lambda = 9 |
Asset |
The price of the underlying asset. Must be > 0. |
TimeStart |
Time, expressed in either Days or Years (depending on the TimeFormat value), until the grant date (when the option forward starts). Must be: 0 < TimeStart < TimeExpire. |
TimeExpire |
Time, expressed in either Days or Years (depending on the TimeFormat value), until the options expiration. Must be: 0 < TimeStart < TimeExpire. |
Volatility |
Annualized volatility of the underlying security. Must be > 0. |
InterestRate |
Risk-free interest rate expressed as a percentage. This rate is interpreted as a continuously compounded rate unless otherwise specified in the InterestType argument. Must be > 0. |
YieldRate |
Yield, expressed as a percentage (dividends or interest yield), of the underlying asset price. This rate is interpreted as a continuously compounded rate unless specified otherwise in the YieldType argument. |
Alpha |
The strike price is set equal to Alpha times the asset price at TimeStart (Strike = Alpha*Asset). Must be > 0 |
MarketPrice |
Optional. The selling price of the option in the marketplace. This input is required when implied volatility and strike are calculated. Price must be > 0. |
TimeFormat |
Optional. Alphanumeric value indicating the format of the time arguments (i.e. TimeExpire). If omitted, Days are used as the default. Specified as either: •Days = 0 or "D" (case insensitive) •Years = 1 or "Y" (case insensitive) |
InterestType |
Optional. Alphanumeric value indicating the type of InterestRate to use when evaluating the option. This value is converted to Continuously Compounded for the calculations. If omitted, a Continuously Compounded rate is used. |
YieldType |
Optional. Alphanumeric value indicating the type of YieldRate to use when evaluating the option. This value is converted to Continuously Compounded for the calculations. If omitted, a Continuously Compounded rate is used. |
Example
Calculate all of functions for a forward start call option with a forward start in 0.25 years and expires in 1 year. The option starts 5% out-of-the money, the asset price is $43, the risk-free interest rate is 6.5% per annum, the yield rate is 3% per annum, and the annual volatility is 20%. All of the rates are considered continuous. So, |
Input |
|
Output |
|||
Variable |
Value |
|
Function |
Name |
Value |
OptionType |
Call |
|
1 |
Theoretical: |
2.461591 |
Asset |
43 |
|
2 |
Delta: |
0.057246 |
TimeStart |
0.25 |
|
3 |
Gamma: |
0.000000 |
TimeExpire |
1 |
|
4 |
Theta: |
0.000202 |
Volatility |
20% |
|
5 |
Implied Vol.: |
0.202666 |
InterestRate |
6.5% |
|
6 |
Vega: |
0.144036 |
YieldRate |
3% |
|
7 |
Rho: |
0.132591 |
Alpha |
1.05 |
|
8 |
Psi: |
-0.157207 |
MarketPrice |
2.5 |
|
9 |
Lambda: |
1.000000 |
TimeFormat |
Years |
|
|
|
|
For a further example on this model see the included Excel Template located in the root directory of the add-in. This example can be accessed through the Multiple Exercise Template menu item after the add-in has been installed properly.
A list of all of the possible Error Messages is included for convenience.