# Questions tagged [correlation]

A measure of the degree of linear association between a pair of random variables.

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104 views

### Monte Carlo simulations of correlated stocks by Geometric Brownian motion

I am trying to simulate using a Geometric Brownian Motion process three autocorrelated stocks. In particular, I need to simulate three different matrices with 1000 scenarios each using a Monte Carlo ...
74 views

### Correlation sensitivity in multivariate $t$-copula for portfolio VaR of electricity futures using Kendall's tau-$b$ correlation matrix

My t-copula model captures the daily dollar returns of a portfolio of approximately 400 assets. I am curious if there's a generally accepted way to quantify the sensitivity of portfolio movements with ...
108 views

### Covariance of mean-reverting Vasicek process?

I am dealing with a mean-reverting Vasicek process defined as: $$S_t = S_0 e^{-at} + b(1-e^{(-at)}) + \sigma e^{(-at)} \int_{0}^{t} e^{(-as)} \ W_t$$ I want to ...
28 views

### What is the appropriate transform before calculating the correlation between two assets?

When calculating the correlation between two assets, what is the appropriate transform before taking the correlation? PChg = (P2/P1) - 1.0 LChg = Log(P2) - Log(P1) x = Log(P2) where P2 is the newest ...
37 views

### Nasdaq and HML factor positive coefficient

I am using the HML factor from Fama French’s website and have always assumed that a negative coefficient indicates that the portfolio has a tilt towards growth stocks. When I however perform a simple ...
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### Are the correlations of multivariate stock prices preserved when converted to multivariate returns?

If data for multiple stock prices has a specific correlation matrix, is the correlation matrix preserved when those prices are converted to multivariate log-differenced returns?
85 views

### Should portfolios have zero or negative correlation between assets? [closed]

Is it more optimal to have a portfolio whose assets are negatively correlated? (I am not requiring all assets to be negatively correlated in this case, nor (-1) perfectly negative correlation either. ...
72 views

### Why does the likelihood of corner solutions in portfolios increase as the number of assets grows?

A three- asset portfolio doesn't seem prone to generating corner solutions, which are very high allocations to one of the assets and $0$ to the others. Instead, when the number of assets is low, these ...
97 views

### Which portfolio is more “diversified”: the $\frac{1}{N}$, the MDP or the max decorrelation?

Equally-weighted portfolio: weights each asset the same $w_i = 1/N$ Maximum diversification portfolio: maximizes the ratio, $\frac{w' \sigma}{\sqrt{w' \Sigma w}}$ Maximum decorrelation portfolio: ...
100 views

### Non-linear correlation (co-dependence) and the efficient frontier

The graph below shows how the efficient frontier for 2 assets bends into a sharp bisection as correlation decreases from $1$ to $-1$, with $\rho=-1$ being the most diversified, and highly unattainable ...
56 views

### comparing volatility and correlation over time

I'm trying to figure out if some emerging markets change over time. First of all I am going to check for changes in volatility. What would be a good method to do this. And do you suggest comparing ...
51 views

### How does the mean-variance model weight negatively correlated assets vs positively correlated ones?

Mainly wondering how the portfolio optimization model weights two stocks that have negative correlation, versus two stocks that have positive correlation. Does the mean-variance model weight them the ...
138 views

### How to annualize the correlation matrix?

If asset returns are daily, and the asset return covariance matrix, $\Sigma$, is annualized by $\Sigma \times 252$, do I also multiply the correlation matrix by 252 to annualize it?
117 views

### How can beta be negative? [closed]

I've been reading about the security market line and the definition of beta as $$\beta_i = \frac{Cov(R_i, R_m)}{Var(R_m)}$$ for any asset (doesn't have to be an efficient portfolio), and have read ...
77 views

### References for deep understanding of correlation matrices

Can anyone suggest some references for learning as much as possible (and in detail!) about correlation matrixes? In particular, would be great to have (among others) covered: algebraic and ...
42 views

### Modelling dependance between the two uncorrelated variables using copulas

Are copulas good tool to model the dependence between the two uncorrelated variables. I have X and Y datasets with 260 data points each with Pearson's correlation=-0.06 and Kendall rank correlation=0....
100 views

### Sharpe from signal to daily return correlation

A few years back in an interview I remember being asked to derive the Sharpe ratio from the correlation between a pre-open daily signal and the open-close returns. I think you had to make some ...
43 views

### Ranking assets by covariance vs correlation

After every change in portfolio (i.e. every trade), I need to calculate a price for each asset in my portfolio. But the calculator is slow. So I want to order the sequence of price updates, from the ...
43 views

### Pearson correlation significance : Issue with $t$-statistic increasing with $N$

I have two assets which seem not correlated (correlation coefficient = 6.3% using monthly frequency and 48 data points). I want to test the significance of the correlation. Null hypothesis is that ...
41 views

### By how much do specific asset correlations increase during a market downturn?

It is well-known that asset return correlations of stocks increase during market downturns. But are there any general properties derived from empirical observation or evidence regarding by how much ...
34 views

### Hedging or Relative Value Strategies with Rho or Tau Correlations?

I understand that the Pearson correlation indicates the strength of linear relationship between two data sets. The applicability of this to hedging strategies is intuitive: If I can establish a linear ...
27 views

### Covariance of Individual Return and Portfolio Return

Hi guys, Is it possible to get the covariance between the individual return and portfolio return given the correlation matrix, volatility matrix, weights matrix and return matrix? I know how to get ...
71 views

### Pairs Trading: Normalized price series (co-integrated and correlated) always end up diverging

Need some expert advice and suggestions: I am trying out pairs trading or statistical arbitrage (as traders say). But even if two price series are co-integrated (ADF test, Hurst exponent, Ornstein–...
27 views

### Do asset return correlations have strong non-linear interactions? [duplicate]

If I compute the correlation matrix for $N$ stocks or indices, are there always expected to be strong non-linear dependencies between each asset pair-wise? Or are there only linear dependencies in ...
57 views

### Wrong way risk exotic option

I've priced an exotic option with Monte Carlo method under the Heston model. Then I want to estimate Wrong way risk. In a paper I've found this method to calculate WWR: WWR can be modeled by means of ...
107 views

### Is non-linear correlation an issue in portfolio optimization?

Portfolio weights are linear combinations of assets. How can it be true then for there to be, and how can someone prove that there is any, non-linear correlation issues in portfolio optimization? Is ...
56 views

72 views

### mixing fractional Brownian motions

Given two Brownian motions $W_t^1, W_t^2$, we can have them correlated by $$W_t^1 = \rho W_t^2+\sqrt{1-\rho^2}Z_t$$ where $W_t^{2}$ and $Z_t$ are independent of each other. My question then: is there ...
40 views

### calibration of correlation in vasicek model

how can I calibrate the correlation by numerical integration of the normal bivariate distribution assuming that the standardized asset returns of two firms are described by the single-factor Vasicek ...
81 views

### realized correlation estimation

I'm trying to implement the Hayashi - Yoshida estimator for correlation (T. Hayashi, N. Yoshida: On covariance estimation of non-synchronously observed diffusion processes, 2005) and there's something ...
19 views

### How can I find the exit equity value from my dataset (please read description and see screenshot below)

I am investigating the returns of private equity using a public market equivalent (PME) and have been given a dataset from the that has provided us with the deal level IRR, the entry equity data and ...