# All Questions

3k views

### Is there a standard model for market impact?

Is there a standard model for market impact? I am interested in the case of high-volume equities sold in the US, during market hours, but would be interested in any pointers.
2k views

### is beta of a portfolio always meaningful?

Consider the following strategies: a stat arb strategy with no overnight exposure, but significant market exposure intraday. a market timing model which is always long or short the market. etc is ...
9k views

### What is the implied volatility skew?

I often hear people talking about the skew of the volatility surface, model, etc... but it appears to me that a clear standard definition is not unanimously in place among practitioners. So here is ...
8k views

### Should I use an arithmetic or a geometric calculation for the Sharpe Ratio?

What are the advantages/disadvantages of using the arithmetic Sharpe Ratio vs the geometric Sharpe Ratio? Is one more correct? Or is one better in certain circumstances?
2k views

### Why do expected return models and risk models use different factors?

This is a question responding to weekly topic challenge. I happen to see an interesting question from SYMMYS by Michael Kapler. I always approached expected return and risk modeling as separate ...
5k views

### Why do we use GARCH(1,1) to predict volatility?

What makes GARCH(1,1) so prevalent in modeling especially in academia? What does this model has that is significantly better than the others?
3k views

### How do I find the most diversified portfolio, or least correlated subset, of stocks?

I have a trading system that chooses top 10 stocks in Nasdaq 100 ranked on relative strength and some other factors. However, I'd like to take positions in only 5 of these 10 stocks based on how ...
7k views

### R: How feasible is it to store — and work with — tick data in a database connected to R?

I'm looking to convert some tickdata .csv files into a database on a local disk and then use R to call the data and do my various analytics and modelling. What are some best practices / ...
2k views

### How to generate a random price series with a specified range and correlation with an actual price?

I want to generate a mock price series. I want it to be within a certain range and have a defined correlation with the original price series. If I choose, say, oil, I want as many time series which ...
3k views

### At what point does someone using technical analysis become a Quant?

Sorry if the question sounds rough. It's not my intention to devaluate something I've not yet understood like Quantitative Finance. So to keep it simple: is Quantitative Finance a science, like ...
2k views

### Categories of systematic trading strategies?

What are the main categories of systematic trading strategies (e.g. momentum, mean reversion), as might be considered by an index or fund-of-fund analyst? Are there any common sub-strategies?
2k views

### Are two identical time series cointegrated?

I did cointegration test on two identical time series, and the result shows that they are not cointegrated, but intuitively, I think they are. Can anyone share some thoughts on this? Thanks!
2k views

### How do you evaluate a covariance forecast?

Suppose you have two sources of covariance forecasts on a fixed set of $n$ assets, method A and method B (you can think of them as black box forecasts, from two vendors, say), which are known to be ...
4k views

### How to combine multiple trading algorithms?

Is it possible to combine different algorithms so as to improve trading performance? In particular, I have read that social media sentiment tracking, digital signal processing and neural networks all ...
2k views

### What are some quantitative approaches to value investment?

As a developer and statistician, I consider value investing to be a statistically sound investment strategy. I've read a few books on the area but I am still not clear on valuation measures. So I ...
1k views

### How to encode trading strategies mathematically

If you have a bunch of different econometric data (e.g. indexes, FX, commodities, interest rates...) you can try to find a formula to see if there is any relationship in the data - e.g. to forecast ...
1k views

### Rate interpolation in Libor Market Model

Libor Market Model (LMM) models the interest rate market by simulating a set of simply compounded, non-overlapping Libor rates which reset and mature on predefined dates. How do I obtain from them a ...
555 views

### How credible is Knight pointing the finger at Rule 107C?

After the Knight Capital incident, I decided to read into the new Rule 107C that NYSE pushed-out August 1st for a one-year pilot. From what I've read, Knight claims that new code rolled out for this ...
6k views

### Free intra-day equity data source

Are there any free data source for historical US equity data? Yahoo finance has daily prices but I'm looking for something more granular and goes back 2 or more years (doesn't have to be close to tick ...
3k views

### Volatility pumping in practice

The fascinating thing about volatility pumping (or optimal growth portfolio, see e.g. here) is that here volatility is not the same as risk, rather it represents opportunity. Additionally it is a ...
596 views

### Issues when considering a quantitative trading/finance firm

I have an upcoming quantitative trading interview (prop desk at a large bank), and I would like to have some good questions to ask about the group. However, I am changing fields from academia and I do ...
1k views

### When should you build your own equity risk model?

Commercial risk models (e.g., Barra, Axioma, Barclays, Northfield) have evolved to a very high level of sophistication. However, all of these models attempt to solve a very broad set of problems. ...
2k views

### Role of skewness in portfolio optimization?

What is the role of skewness in portfolio optimization?
749 views

### What are some research articles on using principle components to generate alpha?

Here's an example by Marco Avellenada from NYU titled "Statistical Arbitrage in the U.S. Equities Market". The idea of this paper involves capturing mean reversion in the residual returns of a ...
1k views

### Is there a popular curve fitting formula of options skew vs strike price or vs Delta?

I was trying to build a options trading/optimization system. But it often gets more inaccurate as it scans through the far from ATM options because, you know, options skews. That is because I did ...
4k views

### How does left tail risk differ from right tail risk?

How does left tail risk differ from right tail risk? In what context would an analyst use these metrics?
2k views

### Papers about risk management in algorithmic trading?

I am currently doing my research for my master thesis, which will clearly focus on the question of risk managment in algorithmic trading systems. I have done research about this topic and found some ...
715 views

### How to price a volatility-index option?

There exist several volatility indices, such as the CBOE Volatility Index (VIX). There are also options on such indicies. What is the best way to price a volatility-index option? Is there a simple ...
1k views

### Topological methods in finance

Recently a promising start-up (Ayasdi) has made headlines. They are a spin-off of the Applied and Computational Algebraic Topology group of Stanford University (ComTop). What they basically do is ...
1k views

### How to build a regime-switching model which knows its own limits?

In recent months I've come to the conclusion that there are not only certain regimes in the markets (like bear or bull) but phases where all models fail because we are in uncharted territory. The ...
3k views

### How do I compare implied and historic volatility?

what would you suggest are the starting points for comparing, in an easy, visual way, implied and delivered volatility surfaces? I'd like to see what the differences are between the historic surfaces, ...
624 views

### Meta-view of different time-series similarity measures?

While I spend most of my StackExchange time on MathematicaSE, I'm in the business and follow the questions and answers on this site with great interest. Recently questions like the following (and ...
343 views

### What approaches are there for stress testing a portfolio?

Wikipedia lists three of them: Extreme event: hypothesize the portfolio's return given the recurrence of a historical event. Current positions and risk exposures are combined with the historical ...
2k views

### Modelling with negative interest rates

For a project, I am interested to model the impact of recently negative interest bonds on the portfolio. The literature on modelling negative interest rates is limited, and the only theory I could ...
2k views

### Value-at-Risk of the sum of two dependent lognormal random variables

Hy I posted this question first at mathflow.net they suggested me this page, which I was not aware of. Question: Let $(X_1,X_2)$ be a multivariate normal random vector ($X_1$ and $X_2$ need not be ...
696 views

### Discrete-time model: stock dynamics

I am working in the area of probability theory and for a case study I would like to make some calculations in finance. Since I am developing theory for the discrete time, I am interested in models for ...
804 views

### Applicability of PCA to get historical volatilities to calibrate interest rates trees

My question in short is as follows: can I take main principal component of historical covariance matrix and use it as historical volatilities when fitting a binomial tree? Here's more detailed ...
2k views

### Is there an open source alternative to Reuters Kondor+?

Basically, I'm looking for a system which have trading(in a demo account), book keeping, profit/loss and risk calculation capability across different asset classes such as bond, repo, equity, foreign ...
522 views

### What time are Bloomberg Open Symbology Files updated daily?

Does anyone know what time the Bloomberg Open Symbology precanned files are updated every day? I am planning on upating my view of them at 9 AM EST every morning. Furthermore, will the files for ...
410 views

### Consistency of economic scenarios in nested stochastics simulation

I am interested in references on research regarding the consistency of economic scenarios in nested stochastics for risk measurement. Background: Pricing by Monte-Carlo: For pricing complex ...
6k views

### What is a martingale?

What is a martingale and how it compares with a random walk in the context of the Efficient Market Hypothesis?
6k views

### Why does implied volatility show an inverse relation with strike price when examining option chains?

When looking at option chains, I often notice that the (broker calculated) implied volatility has an inverse relation to the strike price. This seems true both for calls and puts. As a current ...
939 views

### Keeping a track record honest

I want to start a blog/newsletter and maintain a track record of trades I recommend. I have a never-expiring demo account for this purpose. How do I keep this track record "honest"? Three months ...
3k views

### What are some good technical and non-technical books for a math lover to get in to quantitative analysis? [closed]

To get the ball rolling... I will answer this question this evening For people aware & unaware I think it would be a great way to introduce the group, resources for fundamental knowledge & ...
2k views

### Looking for a recommendation for a real life volatily trading book.

Recently I started working in an algotrading company as a programmer. After I studied that subject a little in the university and read a book or two in that field I gained a little knowledge in that ...
3k views

### Why is the Drawdown measure not used for portfolio optimization?

I was asked yesterday by a colleague why we are doing asset allocation using optimizers which target, for a minimum expected return: the portfolio with the minimum variance or the portfolio with ...
3k views

### References for developing an automated trading system?

I am looking for references on the architecture of automated trading systems and the trading algorithms behind them. I am more interested in system development than analysis. A couple of books I ...
1k views

### Resources for finding scholarly research on topics in quantitative finance?

A friend and I have taken up an interest in quantitative finance, and we're pretty much starting from scratch—neither of us have backgrounds in finance, but rather electrical engineering and ...