variance matrix

How to add a benchmark to a variance matrix

October 1, 2012 | Pat

There is a good way and a bad way to add a benchmark to a variance matrix that will be used for optimization and similar operations. Our examination sheds a little light on the process of variance matrix estimation in this realm. Role of benchmarks Investing Benchmarks are common in ...

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A variance campaign that failed

April 23, 2012 | Pat

they ought at least be allowed to state why they didn’t do anything and also to explain the process by which they didn’t do anything. First blush One of the nice things about R is that new statistical techniques fall into it. One such is the glasso (related ...

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The quality of variance matrix estimation

March 12, 2012 | Pat

A bit of testing of the estimation of the variance matrix for S&P 500 stocks in 2011. Previously There was a plot in “Realized efficient frontiers” showing the realized volatility in 2011 versus a prediction of volatility at the beginning of the year for a set of random portfolios. A reader commented ... [Read more...]

Specific differences between Ledoit-Wolf and factor models

May 22, 2011 | Pat

What can we learn about the difference in structure between a Ledoit-Wolf variance matrix and a corresponding factor model variance? Previously We’ve generated a set of random portfolios with constraints on the risk fractions of a Ledoit-Wolf variance matrix, and a corresponding set of random portfolios with risk fraction ... [Read more...]

Again with Ledoit-Wolf and factor models

May 4, 2011 | Pat

We come closer to a definitive answer on the relative merit of Ledoit-Wolf shrinkage versus a statistical factor model for variance matrices. Previously This post builds on the post entitled: A test of Ledoit-Wolf versus a factor model That post depended on some posts previous to it. New information Previously ... [Read more...]

A test of Ledoit-Wolf versus a factor model

April 27, 2011 | Pat

Statistical factor models and Ledoit-Wolf shrinkage are competing methods for estimating variance matrices of returns. So which is better? This adds a data point for answering that question. Previously There are past blog posts on: the idea of variance matrices factor models of variance The data in this post are ... [Read more...]

Factor models of variance in finance

March 7, 2011 | Pat

In “What the hell is a variance matrix?” I talked about the basics of variance matrices and highlighted challenges for estimating them in finance. Here we look more deeply at the most popular estimation technique. Models for variance matrices The types of variance estimates that are used in finance can ...