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16
votes
6answers
8k views

Python library for Portfolio Optimization

Does anyone know of a python library/source that is able to calculate the traditional mean-variance portfolio? To press my luck, any resources where the library/source also contains functions such as ...
12
votes
5answers
1k 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 ...
11
votes
3answers
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 ...
11
votes
2answers
1k 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 ...
6
votes
5answers
808 views

portfolio optimization from empirical return distributions

I'd like to do a portfolio optimization of a set of ETF's but want to avoid traditional problems with normality assumptions in returns etc. Are there techniques that let me sample 'draws' from the ...
6
votes
1answer
3k views

What is a self-financing and replicating portfolio?

I try to understand the derivation of the Black-Scholes equation based on the "constructing a replicating portfolio". From mathematical point of view it looks simple. We assume that: Stock prices ...
6
votes
2answers
358 views

How do Return.portfolio and Return.rebalancing work in Performance Analytics in R?

I have a question about the function Return.portfolio/Return.rebalancing from the Performance Analytics package in R. I take ...
6
votes
2answers
291 views

How to interpret beta meaningfully?

Although this is probably a basic question, this is probably also the right forum to post it in :) I thought I understood beta, but know I am really confused... The beta between my portfolio (weekly ...
5
votes
4answers
1k views

How can I select the least correlated portfolio of assets?

Can anyone explain the process and the calculations needed to select a portfolio of liquid futures assets with the least correlation? Given a set of returns for a series of assets, how do I select the ...
5
votes
5answers
967 views

How to fit probability density function from sample moments?

If I have calculated the sample mean, variance, skew and kurtosis of a set of data, how would I go about fitting a probability distribution to match these moments (i.e. choosing a probability ...
5
votes
1answer
219 views

RMT (Random Matrix Theory) issue with callibrating MP distribution -

I am seeing an issue when callibrating an MP distribution. Assume a log return series for the SP500 with the following dimensions dim(xts.sp500.ret.stocksonly) ==> [1] 1133 478 ...
5
votes
1answer
423 views

Are there any tools or useful algos for identifying corner portfolios?

Let's say I am performing mean-variance optimization subject to some weight constraints. I'd like to identify the set of corner portfolios so that I can interpolate the entire efficient frontier. A ...
5
votes
1answer
576 views

Risk Budgets with Target Portfolio Volatility

I'm working through the implementation of a risk budgeting approach as described in the recent Roncalli paper. The idea is that the portfolio manager sets a contribution of total portfolio volatility ...
4
votes
2answers
107 views

Portfolio Optimization to include ALL Securities?

I'm currently optimizing portfolio weights for an investment team with N stocks. We buy stocks with a conviction it will generate a return and it is up to me to determine weighting. However, with ...
4
votes
3answers
507 views

Calculating the right portfolio(position size for each leg) in a Long/Short Strategy

For a Long/Short Strategy, I have two stocks with different volatilities. How can I calculate the right position size for each leg? *The pair trading is not coming from co-integration but more as a ...
4
votes
2answers
294 views

Comparing Returns on a Sector Basis

I'd like to compare the returns of a portfolio segregated by groups to the returns of those groups in total. So say for example I have a portfolio with 40% Industrials and 60% Technology, then over ...
4
votes
2answers
372 views

Average correlation of index/portfolio

We try to analyze the average correlation of a portfolio as it can be found here in section 2 b), the same formula which is also used by the CBOE to calculate implied correlations: $$ \rho_{av(2)} = ...
4
votes
1answer
944 views

Michaud's Resampled Efficient Frontier - Out of Sample Simulation Testing

I will be putting ALL my account points on bounty to whoever answers this question [if your answer is crap but it's the only answer, you're getting the 165 points]. You will have to wait 2 days or so ...
4
votes
1answer
182 views

Portfolio optimization with Portfolio CVaR Constraint

I wanted to optimize a portfolio based on a portfolio-wide CVaR constraint (i.e. $CVaR_p \leq 0.08$). Unfortunately, I only find solution that minimizes the entire CVaR of the Portfolio. Do you mind ...
4
votes
0answers
305 views

Shrinkage Estimator for Newey-West Covariance Matrix

I like to apply the Newey-West covariance estimator for portfolio optmization which is given by $$ \Sigma = \Sigma(0) + \frac12 \left (\Sigma(1) + \Sigma(1)^T \right), $$ where $\Sigma(i)$ is the lag ...
3
votes
1answer
151 views

How do I model risks for specific short-term short calls in a portfolio with limited data?

I'm trying to do some risk analysis on a portfolio of bonds, currency, stocks and short calls. The short calls expire in approximately 15-30 days and I've only got around 20 days of pricing data on ...
3
votes
1answer
348 views

analyze strategy performance with given matrix of weights/time and weekly returns in R

I have a matrix of 259 weekly returns, 50 assets and a portfolio composition for each of the 259 weeks. I would like to test the performance of the portfolio during 52 weeks, rebalancing every 12 ...
3
votes
2answers
817 views

Equity option portfolio greeks with underlying

I'm curious about how to construct the five basic greeks for an equity option portfolio when there are shares of the underlying in the portfolio. For example, a portfolio of 100 call options and 100 ...
3
votes
3answers
156 views

How to work out weights for a portfolio based on an inverse ratio with positive and negative values?

I am trying to work out how to determine weights for the assets in order to form a portfolio. The ratio I am using is EV/EBIT, hence the smaller the better. The problem is I don't know how to handle ...
2
votes
1answer
94 views

Correlation of asset to portfolio, given certain variables

Ultimately I'm trying to calculate stdev contribution, but I've hit a hurdle. What I have: 20x20 correlation matrix for various assets Standard deviations for each asset Returns for each asset ...
2
votes
1answer
133 views

Predicting stock returns - in a panel data specification or by using portfolio formation strategies?

I'm working on an empirical analysis where I try to predict stock returns using weekly data. Ideally, I would like to use a panel data model like the following: $$ ...
2
votes
1answer
112 views

Is the volatility of a trader's wealth equal to the volatility of the underlying assets traded?

Assume that a trader trades in several stocks with different volatilities. The return of the trader's portfolio would be the weighted average of returns and the risk would be a function of the the ...
2
votes
1answer
572 views

Using alpha to evaluate trading strategy

I have a trading strategy that generates returns $R_{t}$. I want to test the strategy by looking at the alpha: $R_t - R_{f,t} = \alpha + \beta (R_{m,t} - R_{f,t}) + e_t$ I compare my alpha against ...
2
votes
0answers
124 views

What happened to Mountain View Analytics?

I stumbled over Thomas Cover's work on algorithmic portfolio selection; apparently, an outfit called "Mountain View Analytics" attempted to implement the suggestions from Cover's research. ...
2
votes
1answer
67 views

Why does my posterior mean differs from Idzorek's results?

I have implemented two different expressions (Idzorek p.6, Walters p.51) of a posterior mean return calculation within a Black-Litterman framework. My results are the same, irrespective of the ...
2
votes
0answers
78 views

Portfolio insurance with a coherent risk measure (CVaR)

I would like to analysis of portfolio insurance under a coherent risk-measure method (CVaR), How can I achieve that? Is there a way to turn the problem into a linear programming problem? or to ...
2
votes
0answers
519 views

How to correctly construct a value- and equally weighted portfolio consisting of property-types?

A problem of which I couldn’t find the answer on the forum is about the construction of equally-weighted and value-weighted portfolio. I want to compute the equally-weighted property-type portfolio ...
2
votes
0answers
126 views

Calculating stock weight for SEC13F filers

I am trying to evaluate weight of stocks in portfolio for an investor. For this purpose I use SEC13F filings for particular quarters and historical prices from Yahoo. There are stocks in portfolio ...
1
vote
1answer
219 views

Given a correlation martrix, calculate portfolio's correlation with its assets

Find correlation vector like $[ d e f ]$ where d, e and f represent correlation of P(portfolio) with its assets A, B and C respectively. The assets A, B, C can be another portfolio. In order for ...
1
vote
2answers
147 views

Statistics of difference between two GBMs

if I have two asset prices modeled separately as geometric brownian motions. How do i go about calculating the expected statistics of their difference? Like given the sigmas and mus of both processes, ...
1
vote
1answer
34 views

Geometric Return & Performance Results for Quarterly Rebalancing

I have a Portfolio that is rebalanced every 3-months. The portfolio is made up of assets that have daily log-returns. I am a bit confused when charting the results using ...
1
vote
2answers
69 views

Calculate alpha (CAPM) in “cross country-portfolio”

Assume I wanted to compute the alpha (in CAPM sense, i.e. $r_i - r_f = \alpha_i + \beta_i(r_m - r_f) + \epsilon_i$) of a stock. So I take, say, monthly returns of a stock $i$ for 1 year. Subtract the ...
1
vote
2answers
217 views

Risk management of options

Your client would like to buy a digital call option. the digital call option pays the buyer in one years time (i.e at maturity ) N=1m SGD, if the SGD USD spot rate at maturity is above a prescribed ...
1
vote
2answers
49 views

Distribution of the value of a portfolio

Suppose there are k different stocks in a stock market. All of their prices are independent from each other. One year from now the price of the i-th stock will be $X_i^2$, where $X_i \sim ...
1
vote
1answer
54 views

What do “Exposure Bounds” mean in Portfolio Optimization?

I've just started reading up on Portfolio Optimization models and have come across the use of exposure bounds to mitigate the sensitivity of the optimized model solution, owing to parameter estimation ...
1
vote
1answer
86 views

Arbitrage Strategy Proof in Bjork

In Tomas Bjork's Arbitrage Theory in Continuous Time (or here), $\exists$ this proposition Proposition 2.9 Suppose that a claim X is reachable with replicating portfolio h. Then any price at t=0 of ...
1
vote
3answers
120 views

Greeks of self-financing portfolio

I would like to learn more about the Greeks of portfolios of options: In textbooks and websites, I commonly encounter the unqualified claim that "The Greek measure of a portfolio is the sum of the ...
1
vote
1answer
373 views

Portfolio software that shows 'total return' for each investment

I'm a high school technology teacher and sponsor for the Charity Student Investment Project. Currently our students track our investment portfolio via a google spreadsheet ...
1
vote
1answer
457 views

derivation of formula for portfolio skewness and kurtosis

Where can I find derivation of formula for portfolio skewness and kurtosis? I can find formulas everywhere, but not their derivations? For example, the portfolio variance formula is well known and I ...
1
vote
0answers
21 views

Sharpe Ratio for loans

I am trying to calculate the sharpe ratio for a set of loans. These loans have already matured and I know if they were good or not: grades are the different grades of the loans. interest rate is the ...
1
vote
1answer
36 views

In theory historical performance of a portfolio

I am looking at the quantitative model our team is using for analyzing the performance of a portfolio of stocks. However I don't understand what the model is trying to achieve. The model is supposed ...
1
vote
1answer
55 views

Combine together different strategies in one portfolio

Hi I have generate equity of my strategies which invest in commodities and currencies at daily interval. What the best method to combine together all strategies in one portfolio? I want to make the ...
1
vote
0answers
40 views

how to find CVaR/AVaR for triangular fuzzy no

While going through different methods of risk measure i came across AVaR/CVaR, while i was calculating AVaR/CVaR in credibilistic environment using VaR, i got stuck in the calculations eg. For ...
1
vote
2answers
1k views

Calculate Average Price, Cost, (Un)Realized P&L of a position based on executed trades

We have built an algorithmic trading software and need to calculate the following parameters for each position in our portfolio. Average Price Cost Realized Profit & Loss Unrealized Profit & ...
1
vote
1answer
153 views

Resampled efficient frontier length of simulation

I was provided with a VBA program from my lecturer that applies the resampled efficient frontier. We have an investment horizon $T$ (6 years) and he uses a multivariate normal distribution with ...