Richard Michaud PhD
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Transcript Richard Michaud PhD
Portfolio Monitoring*
Richard Michaud, David Esch, Robert Michaud
New Frontier Advisors
Boston, MA 02110
Presented to:
QWAFAFEW NYC
September 27, 2012
* Forthcoming: Michaud, Esch, Michaud, 2012. “Portfolio Monitoring in Theory and Practice,”
Journal Of Investment Management.
© 2007 Richard Michaud and Robert Michaud
© 2011 Richard Michaud and Robert Michaud
About New Frontier
• Institutional research and investment advisory firm
• Inventors and authors in investment technology
• Michaud and Michaud, Efficient Asset Management, 1998,
Harvard, 2008., 2nd Edition, Oxford
• NFA is unique:
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Institutional investors who use our own software
Global software providers who manage money
Published authors in books and refereed journals
Four U.S. patents, two pending
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Current Portfolio Monitoring Ad Hoc
Calendar rebalancing
Monthly, quarterly, yearly, three years, every five minutes
Asset weight hurdle ranges
Drifted portfolio relative to neutral or optimal weights
Ranges typically vary based on asset volatilities
No theory to support practice
Not portfolio based rules
Often trading in noise or not trading when useful
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True Portfolio Monitoring
A statistical similarity test:
Is the current drifted or given candidate portfolio
statistically similar or different relative to optimal
If statistically similar, don’t trade
If statistically different, trade
Presentation scope:
Decision whether or not to trade
How to trade or how much to trade is a separate issue
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Academic Portfolio Similarity Tests
Shanken (1985), Jobson and Korkie (1985), Levy and Roll
(2010)
Tests of CAPM
Is “market” statistically mean-variance (MV) efficient
Limitations of academic tests
Analytical tests assume unconstrained MV optimization
Hotellings T2 and other analytic methods
Not useful for investment practice
Practice requires linear inequality constraints
Constraints part of defining test statistic
See Markowitz (2005) why constraints essential
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First Constrained Portfolio Similarity Test
Michaud (1998, Ch. 7)
Portfolio distance function relative to Michaud frontier
Uses patented resampling technology
Computes need-to-trade probability
Relative to thousands of simulated investment scenarios
Technology used in NFA’s World Gold Council reports
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Resampling and the Michaud Frontier
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Statistical Portfolio Monitoring Illustrated
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What the Monitoring Rule Computes
Associated simulated optimal portfolios provides a distance
scale for monitoring portfolios
Portfolio distance function (one example)
Relative variance function = (P – P*) (P – P*)
A measure of distance in N-dimensional portfolio space
Sort distance low to high distribution
Defines probability scale from 0 to 99%
Compute distance from current to optimal
Defines probabilistically how far current from optimal
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What the Rule Means
10% need-to-trade probability means
Portfolio distance is 10% as far as others in distribution
75% or more probability may indicate trading is
recommendable
50% probability often a useful default value
Balance between avoiding noise trading and being able to
detect true deviations from optimality.
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Using Portfolio Monitoring Rule
Decide on level of probability for trading
L = Probability level for trading
Recommend trading if probability > L
L depends on many investment and client issues
Investment Styles:
High levels -- value managers?
Lower levels -- growth managers?
Client Preferences, investment horizon
Specialized investment classes
Way to monitor universe of managed accounts
Portfolio monitoring automation
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Limitations of the Original Michaud (1998) Rule
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Limitations of Michaud (1998) Test
Low statistical power
Infrequently rejects no-need-to-trade null hypothesis
Poor power at high end of frontier
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Meta-Resampling Solution
Patented meta-resampling (Michaud and Michaud 2002, 2008)
Associates resampled with Michaud efficient portfolios
Each simulated “parent” MV efficient frontier spawns a
“child” resampled efficient frontier
Associated child resampled efficient frontier portfolios used
to compute distance probability
Greatly enhanced statistical power
Nearly uniform power across frontier
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Michaud Frontier Associated Meta-Resampled Portfolios
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estimated average return (%)
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0
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standard deviation (%)
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Highly Compute Intensive Process
Use better computer technology
Multi-core computers
Network multi-core
Cloud computing
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Still A Persistent Problem in Practice
Need-to-trade probabilities often seemed too
low in actual practice
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The Common Information Issue
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The Common Information Issue
Information in current portfolio often based on similar information in
new optimal
Common information means two portfolios similar all things equal
Need-to-trade probability necessarily small
Test is no-trading-biased in presence of common information
Michaud-Esch-Michaud conditional monitoring rule
A new scale that includes common information
Dramatically enhanced power for many practical applications
Realistically sensitive to changes in current vs. optimal
Three levels of resampling in general case
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Illustrating Conditional Monitoring Algorithm
One year ago optimal portfolio P0
X0= [x1,x2,…,x60] = defines original risk-return distribution
New optimal portfolio P*
Xnew = [x13,x2,…,x72] = defines new risk-return distribution
48 months of common information: [x13,x2,…,x60]
Compute meta-resampled portfolios (simplest case)
Compute k = random draws = 12 from Xnew distribution
Add to common 48 months: [x13,x2,…,x60] = sim distribution
Compute meta-sim optimal and distance to P*
Repeat above many times
Sort and define distance distribution
Compute P0 distance to optimal and percentile in distance
distribution (conditional need-to-trade probability C(k))
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Actual Case: Conditional Monitoring Rule
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Applications
A measure of regime changes in markets
Assume a long-term strategic optimal portfolio
In drifted period
Minimal market volatility – little need to trade
High market volatility – likely need to trade
Return distribution generalizations
Simulations can be based on any distribution
We generally use t-distribution
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Summary
Portfolio monitoring an essential asset management function
Prior methods ad hoc, academic methods invalid
Patented first practical monitoring rule Michaud (1998)
Limited statistical power
Patented Meta-resampling rule Michaud and Michaud (2002)
Enhanced statistical power across frontier
Customizable to asset management processes
Michaud-Esch-Michaud conditional monitoring algorithm
Common information, increased statistical power
Highly compute intensive procedures
Just finance catching up to real statistics
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Extensions
Potential for large-scale automatable portfolio monitoring
A statistical context for general quadratic programming applications
Process monitoring and multivariate regression in the context of
linear constraints and overlapping data
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© 2011 New Frontier Management Company, LLC
Thank You
New
NewFrontier
FrontierAdvisors,
Advisors,LLC
LLC
Boston,MA
MA 02110
02110
NFABoston,
SAA
Portfolios
www.newfrontieradvisors.com
www.newfrontieradvisors.com
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© 2011 New Frontier Management Company, LLC
Richard O. Michaud
President, Chief Investment Officer
Co-inventor (with Robert Michaud) of Michaud Resampled
Efficient Frontier™, three other patents, two pending
Author: Efficient Asset Management, 1998. Oxford
University Press, 2001, 2nd Edition 2008 (with Robert
Michaud)
Many academic and practitioner refereed journal articles
CFA Institute monograph on global asset management.
Prior positions include:
Acadian Asset Management; Merrill Lynch
Graham and Dodd winner for work on optimization
Former Director and research director of the “Q” Group
Advisory Board member, Journal Of Investment
Management
Former Editorial Board member Financial Analysts
Journal, Journal Of Investment Management
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© 2011 New Frontier Management Company, LLC