Components of Portfolio Variance

18 Pages Posted: 9 Jul 2014 Last revised: 5 Apr 2015

See all articles by Anders G. Ekholm

Anders G. Ekholm

Priceff Ltd; Lappeenranta University of Technology (LUT); University of Helsinki

Date Written: April 5, 2015


An investment portfolio’s return variance is the sum of variance generated by passive systematic risk factor exposure, active security selection and active systematic risk factor timing. We show that the components of active risk can be estimated without knowledge of portfolio holdings. In a broad sample of US equity mutual funds classified as actively managed by Lipper in years 2000-2013, Carhart (1997) risk factors on average account for 94 %, security selection for 5 % and risk factor timing for 1 % of total variance. Security selection is positively associated to future performance, while systematic risk factor timing correlates negatively with future performance. Our new active variance measures – SelectionShare and TimingShare – complement ActiveShare and TrackingError in predicting future performance.

Keywords: selection, timing, performance, Tracking Error, ActiveShare

JEL Classification: G10, G11, G20, G23

Suggested Citation

Ekholm, Anders G., Components of Portfolio Variance (April 5, 2015). Available at SSRN: or

Lappeenranta University of Technology (LUT) ( email )


University of Helsinki


Do you have a job opening that you would like to promote on SSRN?

Paper statistics

Abstract Views
PlumX Metrics