Article: Multi-period portfolio optimisation with alpha decay Journal: International Journal of Financial Engineering and Risk Management (IJFERM) 2018 Vol.2 No.4 pp.283 - 307 Abstract: The traditional Markowitz MVO approach is based on a single-period model. Single period models do not utilise any data or decisions beyond the rebalancing time horizon with the result that their policies are <i>myopic</i> in nature. For long-term investors, multi-period optimisation offers the opportunity to make <i>wait-and-see</i> policy decisions by including approximate forecasts and long-term policy decisions beyond the rebalancing time horizon. We consider portfolio optimisation with a composite alpha signal that is composed of a short-term and a long-term alpha signal. The short-term alpha better predicts returns at the end of the rebalancing period but it decays quickly, i.e., it has less memory of its previous values. On the other hand, the long-term alpha has less predictive power than the short-term alpha but it decays slowly. We develop a simple two stage multi-period model that incorporates this alpha model to construct the optimal portfolio at the end of the rebalancing period. We compare this model with the traditional single-period MVO model on a simulated example from Israelov and Katz (2011) and also a large strategy with realistic constraints and show that the multi-period model tends to generate portfolios that are likely to have a better realised performance. Inderscience Publishers - linking academia, business and industry through research

Title: Multi-period portfolio optimisation with alpha decay

Authors: Kartik Sivaramakrishnan; Vishv Jeet; Dieter Vandenbussche

Addresses: Axioma Inc., 400 Northridge Road, Suite 550, Atlanta, GA 30350, USA ' The Burgiss Group, 111 River Street, 10th Floor, Hoboken, New Jersey 07030, USA ' Axioma Inc., 400 Northridge Road, Suite 550, Atlanta, GA 30350, USA

Abstract: The traditional Markowitz MVO approach is based on a single-period model. Single period models do not utilise any data or decisions beyond the rebalancing time horizon with the result that their policies are myopic in nature. For long-term investors, multi-period optimisation offers the opportunity to make wait-and-see policy decisions by including approximate forecasts and long-term policy decisions beyond the rebalancing time horizon. We consider portfolio optimisation with a composite alpha signal that is composed of a short-term and a long-term alpha signal. The short-term alpha better predicts returns at the end of the rebalancing period but it decays quickly, i.e., it has less memory of its previous values. On the other hand, the long-term alpha has less predictive power than the short-term alpha but it decays slowly. We develop a simple two stage multi-period model that incorporates this alpha model to construct the optimal portfolio at the end of the rebalancing period. We compare this model with the traditional single-period MVO model on a simulated example from Israelov and Katz (2011) and also a large strategy with realistic constraints and show that the multi-period model tends to generate portfolios that are likely to have a better realised performance.

Keywords: multi-period portfolio optimisation; mean-variance optimisation; alpha decay.

DOI: 10.1504/IJFERM.2018.094030

International Journal of Financial Engineering and Risk Management, 2018 Vol.2 No.4, pp.283 - 307

Received: 15 Feb 2017
Accepted: 17 Dec 2017
Published online: 13 Aug 2018 *

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Title: Multi-period portfolio optimisation with alpha decay

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