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Dec 7

#### Predicting Heavy and Extreme Losses in Real-Time for Portfolio Holders

Posted by abiao at 00:57 | Code » Other | Comments(10) | Reads(7936)
Pawel wrote a great article on predicting heavy and extreme losses in real-time for portfolio holders, the goal is to calculate the probability of a very rare event (e.g. a heavy and/or extreme loss) in the trading market (e.g. of a stock plummeting 5% or much more) in a specified time-horizon (e.g. on the next day, in one week, in one month, etc.). The probability. Not the certainty of that event.

In this Part 1, first, we look at the tail of an asset return distribution and compress our knowledge on Value-at-Risk (VaR) to extract the essence required to understand why VaR-stuff is not the best card in our deck. Next, we move to a classical Bayes’ theorem which helps us to derive a conditional probability of a rare event given… yep, another event that (hypothetically) will take place. Eventually, in Part 2, we will hit the bull between its eyes with an advanced concept taken from the Bayesian approach to statistics and map, in real-time, for any return-series its loss probabilities. Again, the probabilities, not certainties.

Read this excellent post and accompanying Pathon codes at http://www.quantatrisk.com/2015/06/14/predicting-heavy-extreme-losses-portfolio-1/
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Jun 10

#### Option pricing models implemented in AirXCell

Posted by abiao at 21:23 | Code » Other | Comments(1) | Reads(7272)
AirXCell is an online R application framework currently supporting a programmable spreadsheet, an R development environment and various financial calculation forms.

A new calculation form has been implemented recently within AirXCell for financial option pricing (option valuation). The option pricer within AirXCell enables the user to compute theoretical option prices. It already offers an extended set of basic and exotic models (about a dozen) than enables the user to price a wide range of option types:

American options,
European options,
Asian options,
Barrier options,
Binary options,
Currency translated options,
Lookback options,
Multiple assets options and
Multiple exercises options

Many more models are being implemented currently and will be added soon to AirXCell. In addition to the option pricing form, there are other forms especially useful in the same context that provides ways to load asset prices, visualize them, compute the theoretical and historical volatility.

This form is very valuable to quantitative researchers or any finance professional who needs to compute theoretical option prices easily and who is looking for a reliable option pricer.

The Option pricing form presents the user with an HTML form enabling her to set up the model with the required parameters values such as the underlying asset price, the strike price, the volatility of the underlying asset, etc.

For instance, the following form is presented to a user requesting the price of an european option using the Generalized Black Scholes model:

Again, there are many more models and option types coming soon as well as other forms for various other kind of calculations, still mostly oriented towards financial calculation.
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Jan 16

#### Top 20 Movies For Business Men

Posted by abiao at 21:34 | Code » Other | Comments(16) | Reads(16784)
It is difficult to survive in a complicated business world without sound knowledge on economics, management, law, the ways of doing business, etc. Some top business school teaches its MBA students the knowledge, but not everyone is (indeed, only a few are) fortunate enough to enter Harvard, Stanford, or Wharton. Below is a list of top 20 movies that a business man needs to watch, some of them are even highly recommended by those business school professors. You will have a better understanding of the principles and rules of how the business world runs, it will help your career as well.

Disclaimer: the videos are embedded from Youtube uploaded by others, some are full version and others are Trailer. Please consider to buy the movies from Amazon.

### 1, Wall Street (1987)

A young and impatient stockbroker is willing to do anything to get to the top, including trading on illegal inside information taken through a ruthless and greedy corporate raider who takes the youth under his wing.

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Jan 9

#### Online Option Pricing Models

Posted by abiao at 14:37 | Code » Other | Comments(0) | Reads(7505)
Online option calculator was shared several time before, for example, the post online derivative calculator, On-Line Options Pricing & Probability Calculators, etc. Today I came across another very clean website: online Option Pricing Models.

As the website describes:
You can get the price (and the Greeks) of the available options by applying several methods:

- Black & Scholes model for european options and greeks calculation.
- Bjerksund & Stensland model for american options.
- Binomial model (Cox, Ross & Rubinstein, Jarrow-Rudd Risk Neutral, Tian) for american and european options.
- Shifted Lognormal model for european options.
- Partial Differential Equation (PDE) approach: Finite Difference (FD) and Radial Basis Function (RBF) methods for american and   european options.
- Monte-Carlo for digital option (Cash-or-Nothing) and european options and greeks estimation (FD and Malliavin).

Volatility models (SABR with calibration, Lognormal model, etc.) are also available.

I randomly tested the option calculators, they are working well, on top of that, the site is created by a French master student. So it is fine to give him credit with a separated post. Check it at http://pricing-option.com/Default.aspx.
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Oct 9

#### Fast Least Squares Monte Carlo Simulation for American Option

Posted by abiao at 11:42 | Code » Other | Comments(0) | Reads(13144)
We know least-squares Monte Carlo simulation to price an American option is time consuming because it involves optimal exercise decision on every step of a large number of simulation (in the least square case, to run a polynomial regression on cash flows and decide whether it is optimal to exercise or not). I once shared a simple Matlab file to illustrate the least squares Monte Carlo simulation. The situation becomes worse if we allow the presence of stochastic volatility and interest rate, typically my codes run quite a few minutes for 50,000 number of simulations.

In the paper "Fast Monte Carlo Valuation of American Options under Stochastic Volatility and Interest Rates" by Y. Hilpisch, the author demonstrates with Python script that the Least-Squares Monte Carlo (LSM) algorithm with control variates takes only less than one second to achieve satisfying accurateness. The overall statistics taken from the paper are as follows, AMAZING!