Questions tagged [black-litterman]

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Labeling Returns in 5 categories based on BL view approach

I have to label a time series of returns into 5 categories based on the Black Litterman view approach. The categories should look as follows: very bullish: + 2 std. dev. bullish: + 1 std. dev. ...
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45 views

Rationale for likelihood function parameter choice in Black-Litterman model?

So we are interested in a PDF for equilibrium returns given the views. Why do we choose our view means as the mean parameter and observed market covariance as the covariance parameter? Seems a bit ...
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68 views

Black-Litterman risk aversion

I'm trying to better understand how BL works and what I would like to know if there is a way to adjust the portfolio created based on a risk aversion variable determined by the user. I can't really ...
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68 views

Black-Litterman proof with P=I and Omega=tau*Sigma

Elsewhere on this site (link), Richard notes that \begin{equation} \Pi_{BL} = \frac{1}{2} \Pi + \frac{1}{2}Q, \end{equation} so long as we set $ P = I $ (where $I$ is the identity matrix) and $\Omega ...
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1answer
105 views

How to calculate market capitalization weights for a currency portfolio?

I am implementing Black-Litterman optimization on a currency portfolio and I could not calculate market capitalization weights for currencies. Please give me some suggestion.
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62 views

Black-Litterman implied returns using rolling window

I am building an active risk-based Portfolio with a risk-based Portfolio such as the minimum variance Portfolio as the neutral starting point. Therefore, I calculate the rolling 36 month covariance ...
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1answer
185 views

Implied Equilibrium Returns Example

I've been trying to work through a simple example using A Step-by-Step Guide to the Black Litterman Model, but I'm having trouble understanding implied risk aversion. Say I have two uncorrelated ...
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98 views

Black Litterman - numerical instability

I am trying to work out the formula for the posterior mean in Black Litterman's model assuming 100% confidence : Ref: https://corporate.morningstar.com/ib/documents/MethodologyDocuments/IBBAssociates/...
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1answer
365 views

Struggling with tau in Black-Litterman

According to the omega formula in B-L tau is used in the Omega estimation to determine the degree of uncertainty given to views of the investor: So, if tau is given a low value then the inverse of ...
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42 views

References for Risk Adjusted Portfolio Optimization

I'm trying to formulate BL portfolios which use Mean VaR, Mean CVaR optimization to calculate risk-adjusted equilibrium returns. Can someone point me to any references on this topic? I'm looking for ...
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141 views

Problems with Black-Litterman: negative portfolio weights, and very poor returns

I am trying to implement the Black-Litterman model using own-defined views matrix (from consensus analysts). However, I have encountered the problems of negative portfolio weights in some periods, and ...
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1answer
115 views

Can Black-Litterman-type expected return estimation be used for regional ETFs?

The Black-Litterman approach to return estimation overcomes the problems associated with estimating expected returns via historical averages by determining the equilibrium returns implied by the ...
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1answer
229 views

black litterman for rebalancing

I've noticed in my backtests that "shrinking" the expected returns vector towards zero tends to improve the performance. This has led me to investigate shrinkage methods for the forecasts/expected ...
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1answer
572 views

CVXPY 's constrains doesn't work

I am trying to implement a max return optimization with a large number of assets. I am not sure why this problem won't work. ...
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1answer
1k views

How to generate the views in Black-Litterman model?

I want to apply a Black-Litterman approach for portfolio optimization. My question is how to select investor views? I need to base the choice on a model. I would be thankful if you could give me some ...
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34 views

Black Litterman with strongly skewed/leptokurtic variables

I am trying to apply a BL-like model to a random variable which is strongly skewed and leptokurtic. The random variable is actually the change through time of GARCH conditional variance $\sigma_{t+1}^...
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1answer
162 views

Can I formulate a general relative view in Black-Litterman?

We have often discussed the Black-Litterman approach/model in the forum. What I was wondering is: is it possible to formulate relative views in the model. Relative in the sense $$ \mu_1 > \mu_2 $$ ...
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1answer
247 views

Black Litterman: Is it possible to have multiple views (from different sources) on the same asset?

From the basics of Black Litterman I understand that each view on a stock is implemented via the pick matrix P with the expected value of the views in Q. I have read several papers where each stock ...
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2answers
648 views

Is it possible to deal with non-normal distribution in Black-Litterman model?

Suppose that I know that the normality assumption about my data is unrealistic (as it is very frequently): is it possible to apply any distribution that I judge the right one to the Black-Litterman ...
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1answer
194 views

Systematic Views in Black-Litterman?

Are there any literature on selecting systematic views for Black-Litterman along with methods to specify the uncertainty parameter? For example, rather than specifying a portfolio manager's subective ...
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2answers
711 views

Black-Litterman: Why should the views be independent of each other?

This question relates to this question. In the Black-Litterman framework views of inverstors on the market are modelled. These views have a covariance-matrix $\Omega$. I always found it quite ...
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2answers
1k views

Black-Litterman, how to choose the uncertainty in the views $\Omega$ for smooth transitions form prior to posterior

In Black-Litterman we get a new vector of expected returns of the form: \begin{align} \Pi_{BL} = \Pi + \underbrace{\tau \Sigma P^T[P\tau\Sigma P^T+\Omega]^{-1}}_{\text{correction}}[Q-P\Pi] \end{align} ...
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746 views

Black-Litterman with simple portfolio

In an attempt to learn Black-Litterman I have come across this "simple" example. Suppose that you analyze market data using CAPM $$r_i-r_f=\beta_i(r_m-r_f)+\epsilon_i$$ Suppose there are 2 assets in ...
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1answer
331 views

Is an arbitrary prior for Black-Litterman valid? Or do we need a market implied one?

I went through The Black-Litterman Approach: Original Model and Extensions - see also. The BL approeach starts with a prior on the expected returns vector derived from the hypothesis that the market ...
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3answers
2k views

What is the tau parameter in the Black-Litterman model?

Could someone please provide me with a clear and concise definition of the $\tau$ parameter in the Black-Litterman model? It seems one is rather hard to come by. I understand it to be the 'weight on ...
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2answers
2k views

Market weights for Black-Litterman

I'm trying to implement Black-Litterman for an arbitrary selection of assets. One of the input for BL is the "Equilibrium market capitalization weights for each asset". In most examples I've seen, ...