Cesar Alvarez

Author Archives: Cesar Alvarez

How much does not having survivorship free data change test results?

Over the last month several people have asked me how important it is to have survivorship-free data. For any researcher this is an important question to understand how the different data can change your results. We will be exploring three potential data issues: as traded prices, delisted stocks (survivorship-bias), and historical index constituents (pre-inclusion bias).

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February 3, 2014

S&P500 Monthly Rotation-Readers’ Ideas

The ‘Intermediate Term Stock Rotation Strategy Using S&P500 Stocks post generated lots of reader suggestions on what to investigate further.

 

The ideas we will investigate are:

  • Monthly rotation (instead of quarterly)
  • Using an additional filter to make sure the stock is healthy. These include
    • Close above 200 day moving average
    • Close above 50 day moving average
    • 50 day moving average above 200 day moving average
    • Stock return over look back period is positive
    • In the last 10 days the stock has made a 1 month high
    • In the last 10 days the stock has made a 3 month high
    • Maximum loss stops

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January 23, 2014

The issues with back testing a short stock strategy

I have been shorting stocks since 2006 using a quantified strategy that has remained relatively unchanged through the years. From 2006 to 2012, the strategy was one of my most consistent and profitable of all the strategies I have traded. I love shorting stocks because it is very hard psychologically, because of that, I believe that there is a good edge there. The test results have always bothered me because of the differences between back tested assumptions that sometimes are challenging to actually reproduce in real-world trading. Then in 2013 my fears became realized and all four fears below really hit me.

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January 13, 2014

Intermediate Term Stock Rotation Strategy Using S&P500 Stocks

One of my research goals for this year is to find an intermediate term rotation strategy using S&P500 stocks. Then right on cue, I read the following post Intermediate momentum! which points to  research Is momentum really momentum? by Robert Novy-Marx. In that he mentions that “intermediate horizon past performance, measured over the period from 12 to seven months prior, seems to better predict average returns than does recent past performance.” I have never tried an idea like this. In the blog comments, a user says he got great results using the current NDX100 stocks not the historical. This introduces pre-inclusion bias but maybe the results will still be good. What a great way to start the year with ideas I have never tested.

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November 25, 2013

Percent S&P500 Stocks Trading Above MA50 as Market Timing Indicator

Does the percent of S&P500 stocks trading above their 50 day moving average predict future market returns? Over the last several weeks, I have seen several charts of the percent of S&P500 stocks trading above their 50 (or 200) day moving average overlaid on the S&P500. From these charts, it appears one could build a market timing indicator. The concept really looks like it has promise.

SP500-MA50Perc1

Chart from April to November 2013.

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