The LookbackPFloat function calculates the theoretical price, sensitivities, the implied volatility, and the implied strike value of a European partial-time floating strike lookback option using Heynen and Kat’s model. See Lookback Options for a further explanation.
LookbackPartialFloat |
(OptionType, ModelStatistic, Asset, Strike, Lambda, TimeStart, TimeExpire, Volatility, InterestRate, YieldRate, MarketPrice, TimeFormat, InterestType, YieldType) |
Note: Optional arguments are shown in Italics. MarketPrice is not Optional for the Implied Calculations.
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 •StrikeSensitivity = 11 •ImpliedStrike = 13 |
Asset |
The price of the underlying asset. Must be > 0. |
Strike |
The price at which the asset can be purchased if the option is a call or sold if the option is a put. Must be > 0. |
Lambda |
The percentage of the strike that is fixed above or below the actual extreme. |
TimeStart |
Time, expressed in either Days or Years (depending on the TimeFormat value), until the beginning of the lookback period. 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. |
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. |
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 the all of function of a partial-time floating strike lookback call option whose asset price 60 days from expiration is $83, the exercise price is $80, the fractional percentage of the extreme is 1, the time until the beginning of the lookback period is 30 days, the risk-free interest rate is 5% per annum, the yield rate is 4.5% per annum, and the annual volatility is 30%. All of the rates are considered continuous. So, |
Input |
|
Output |
|||
Variable |
Value |
|
Function |
Name |
Value |
OptionType |
Call |
|
1 |
Theoretical: |
7.066447 |
Asset |
83 |
|
2 |
Delta: |
0.345154 |
Strike |
80 |
|
3 |
Gamma: |
0.082245 |
Lambda |
1 |
|
4 |
Theta: |
-0.069281 |
TimeStart |
30 |
|
5 |
Implied Vol.: |
0.296676 |
TimeExpire |
60 |
|
6 |
Vega |
0.199974 |
Volatility |
30% |
|
7 |
Rho: |
0.076726 |
InterestRate |
5% |
|
8 |
Psi: |
-0.088342 |
YieldRate |
4.5% |
|
9 |
Lambda: |
4.054060 |
MarketPrice |
7 |
|
11 |
Strike Sensitivity: |
-0.269767 |
TimeFormat |
Days |
|
13 |
Implied Strike: |
80.257192 |
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 Lookback Template menu item after the add-in has been installed properly.
A list of all of the possible Error Messages is included for convenience.