May
1
When the “Best Six Months” Are Bad, from Steve Ellison
May 1, 2020 |
From 1951 to 2019, there were 15 6-month periods ending on April 30 in which the S&P 500 index declined. The average net change over the next 6 months was -3.8%, a statistically significant underperformance compared to the 4.2% average 6-month gain during the entire 69-year period.
Date Index close net change last 6 months net change next 6 months
4/29/1960 54.37 -5.5% -1.8%
4/30/1962 65.24 -4.9% -13.4%
4/29/1966 91.06 -1.5% -11.9%
4/30/1970 81.52 -16.1% 2.1%
4/30/1973 106.97 -4.1% 1.2%
4/30/1974 90.31 -16.6% -18.2%
4/29/1977 98.44 -4.3% -6.2%
4/30/1982 116.44 -4.5% 14.8%
4/30/1984 160.05 -2.1% 3.8%
4/30/1990 330.8 -2.8% -8.1%
4/29/1994 450.91 -3.6% 4.8%
4/30/2001 1249.46 -12.6% -15.2%
4/30/2008 1385.14 -10.6% -30.1%
4/30/2009 872.81 -9.9% 18.7%
4/29/2016 2065.3 -0.7% 2.9%
Average -3.8%
Standard deviation 12.8%
N 15
t -2.42
Average of all 6 month periods 4.2%
Hernan Avella writes:
Thanks Steve. Some notes:
- If you include the monthly data from 1928 (free yahoo finance), you effect disappears the average next 6 month goes from -3.80% to -0.12%
- Since you have such a small sample perhaps better to look at the trimmed mean or the median……the median of your sample is -1.8%
- Another (arguably better) way to check for significance is calculate your own p value with the bootstrap and the empirical distribution of 6 month returns, using the trimmed mean and winsorized variance.
- Related to above, Victor recommended a fine book a while back.
- Whether one can make more money adding this layer of complexity is still to be determined.
Comments
WordPress database error: [Table './dailyspeculations_com_@002d_dailywordpress/wp_comments' is marked as crashed and last (automatic?) repair failed]
SELECT * FROM wp_comments WHERE comment_post_ID = '12765' AND comment_approved = '1' ORDER BY comment_date
Archives
- January 2021
- December 2020
- November 2020
- October 2020
- September 2020
- August 2020
- July 2020
- June 2020
- May 2020
- April 2020
- March 2020
- February 2020
- January 2020
- December 2019
- November 2019
- October 2019
- September 2019
- August 2019
- July 2019
- June 2019
- May 2019
- April 2019
- March 2019
- February 2019
- January 2019
- December 2018
- November 2018
- October 2018
- September 2018
- August 2018
- July 2018
- June 2018
- May 2018
- April 2018
- March 2018
- February 2018
- January 2018
- December 2017
- November 2017
- October 2017
- September 2017
- August 2017
- July 2017
- June 2017
- May 2017
- April 2017
- March 2017
- February 2017
- January 2017
- December 2016
- November 2016
- October 2016
- September 2016
- August 2016
- July 2016
- June 2016
- May 2016
- April 2016
- March 2016
- February 2016
- January 2016
- December 2015
- November 2015
- October 2015
- September 2015
- August 2015
- July 2015
- June 2015
- May 2015
- April 2015
- March 2015
- February 2015
- January 2015
- December 2014
- November 2014
- October 2014
- September 2014
- August 2014
- July 2014
- June 2014
- May 2014
- April 2014
- March 2014
- February 2014
- January 2014
- December 2013
- November 2013
- October 2013
- September 2013
- August 2013
- July 2013
- June 2013
- May 2013
- April 2013
- March 2013
- February 2013
- January 2013
- December 2012
- November 2012
- October 2012
- September 2012
- August 2012
- July 2012
- June 2012
- May 2012
- April 2012
- March 2012
- February 2012
- January 2012
- December 2011
- November 2011
- October 2011
- September 2011
- August 2011
- July 2011
- June 2011
- May 2011
- April 2011
- March 2011
- February 2011
- January 2011
- December 2010
- November 2010
- October 2010
- September 2010
- August 2010
- July 2010
- June 2010
- May 2010
- April 2010
- March 2010
- February 2010
- January 2010
- December 2009
- November 2009
- October 2009
- September 2009
- August 2009
- July 2009
- June 2009
- May 2009
- April 2009
- March 2009
- February 2009
- January 2009
- December 2008
- November 2008
- October 2008
- September 2008
- August 2008
- July 2008
- June 2008
- May 2008
- April 2008
- March 2008
- February 2008
- January 2008
- December 2007
- November 2007
- October 2007
- September 2007
- August 2007
- July 2007
- June 2007
- May 2007
- April 2007
- March 2007
- February 2007
- January 2007
- December 2006
- November 2006
- October 2006
- September 2006
- August 2006
- Older Archives
Resources & Links
- The Letters Prize
- Pre-2007 Victor Niederhoffer Posts
- Vic’s NYC Junto
- Reading List
- Programming in 60 Seconds
- The Objectivist Center
- Foundation for Economic Education
- Tigerchess
- Dick Sears' G.T. Index
- Pre-2007 Daily Speculations
- Laurel & Vics' Worldly Investor Articles