John Dodson:hi Holly Holly Borgie:Hello Greg:I can hear. Hi John. John Dodson:ok thanks Greg:John, each time I try, I get a negative beta for CSCO. Omega and alpha are positive, though. Have you had success with CSCO this time around? Holly Borgie:that one was pesky for me too Holly Borgie:I didn't get a negative beta though when I changed my starting values, but the numbers look kind of odd John Dodson:I got valid answers, but they were out of line with the others for CSCO John Dodson:A much higher omega and a lower beta Greg:Thanks. I'll keep trying. Scott:could we get the conference call going? John Dodson:Scott, I can open it if it is necessary. What do others think about opening the phone line? Greg:Sounds fine. I'll dial in. Scott:whats the number again? sangya:i'm getting a negative beta for that one too John Dodson:Sangya, do you have the little yellow telephone icon in the corner? roll over that. sangya:biz days Holly Borgie:John, quick question. Can I give you a workbook with Bloomberg links in it, or do you want me to remove them? John Dodson:Holly, you should probably sever links. I don't have Bloomberg on my mac. Holly Borgie:ok, sounds good. John Dodson:thanks. John Dodson:If you are fighting with negative betas, I recommend you re-formulate your problem in terms of log(alpha) and log(beta). John Dodson:The log transofrmation is easy to do and it prevents negative alphas and betas (although not necessarily negative omegas). sangya:i'll try that Greg:Here's an off-topic question. Do you know who our next instructor is, and if he/she has a website? The MFM site doesn't ever seem updated with current instructor website information. John Dodson:Greg, it is Blaise Morton. He is a local fixed income arb manager. I don't think he has a website. Greg:Ok. Thanks. John Dodson:The third instructor is Arkady Shemyakin, who is a local academic. He will have a website. I don't know if he will broadcast or record sessions. I am pretty sure Blaise won't. Holly Borgie:confirmed - I emailed him - he won't be recording sangya:i keep getting an error that says to increase MaxFunEvals option. does that mean there is probably something wrong with my code? any idea? John Dodson:Sangya, it probably has to do with your initial guess. Maybe it is spending too much time looking at negative values. sangya:oh ok...maybe the log transformation will help sangya:I have to get going, thanks john John Dodson:ok, bye Sangya yiran 3:John, all gammas here are negative? John Dodson:Yiran, I have found that gammas are generally negative. I was surprised at the non-negative value for GOOG yiran 3:me too... yiran 3:Is it a lot of work to figure out queation 2? John Dodson:Yiran, I don't think so. But you have to be a little careful. You have to loop over all possible pairs of dates and measure the concordance for each pair of stocks for each pair of dates. yiran 3:thanks! yiran 3:Is that to say, when 11.2 is coming, we can check our model to see whether it is good or not, if nothing unusual happens? John Dodson:no, the prices on 11.2 won't tell you much about their risks as of 10.19. yiran 3:So what is question 1 for? John Dodson:Yiran, from the point of view of 10.19, the prices on 11.2 are random and we can only describe them as random variables. Once the market closes on 11.2, they are no longer random. John Dodson:But we still need to work with a model for risk on 10.19, becasue we have to make investment decisions. yiran 3:Okay. Variance just tell us the volatility. So how can I know whether I should buy or sell. To check the trend of prices? John Dodson:Yiran, it will make more sense once we introduce models for investor preferences next term. yiran 3:ok John Dodson:Generally you will buy when the risk is small and buy when it is large. John Dodson:sorry... sell when he risk is too large yiran 3:make sense John Dodson:But "risk" will be evaluated in a portfolio setting with a particular investor preference. Grant:John, I'm having a little trouble getting from the scaled h to the return forecast. I have h_T+10 and m_T+10 is zero, but what should I use for Z_T+10 to get Y_T+10? John Dodson:Grant, you need something like $h_+E[h_]+E[h_]+\cdots+E[h_]$ John Dodson:This will be your variance forecast for the log-return John Dodson:which you need to convert into a standard deviation forecast for the price Grant:ok, that helps. Thank you. Mac:John, is $h_+E[h_]+E[h_]+\cdots+E[h_]$ or $h_T+E[h_]+E[h_]+\cdots+E[h_]$. Which one is correct for the forecast? John Dodson:Mac, the last $h$ from your quasi-MLE objective function was the forecast for the last residual that you observed. From this, you can forecast the one-day ahead residual based on the updating equation. John Dodson:This is for the return on 10.20. From here you have to use the expectations, conditional on 10.19, for the conditional variances out to 11.2 John Dodson:There should be ten terms Mac:ok! Thanks. John Dodson:Any other questions? I will be here until 9:00 in any case. Grant:none for me. Thanks, John. Have a good night. Greg:Thanks for your help, John. Have a good night. John Dodson:bye Greg Noppanan:Thank you John. Bye