Eminent Speaker: Antti Petajisto on underperformance of concentrated stock positions

Wednesday 01 May 2024 | 17:00 - 18:00 | Eminent Speaker Series, Webinar

Antti Petajisto is the co-author of How active is your fund manager? A new measure that predicts performance in which he famously created a statistic called ‘active share’. This paper was downloaded from SSRN (Social Science Research Network) over 30,000 times. For a considerable amount of time this was the most downloaded paper on the network. Now, Antti, Head of Equities at Brooklyn Investment Group, will be giving CFA UK members insights on his latest paper on concentrated stock positions.  

Contrary to standard investment advice, many high-net-worth investors hold concentrated individual stock positions exceeding 10%. While most investors realise this increases portfolio volatility, they may not understand that it  contributes negatively to portfolio returns.  

Since 1926 a startling truth has revealed that the median individual US stock has consistently underperformed the broader equity market over ten-year periods, by –7.9%, or –0.82% per year.  

But fear not!  Antti will help you understand  the untapped potential of diversification, ensuring that you and your clients avoid any unexpected drag on portfolio returns. 

Registration: 16:55

Event: 17:00 - 18:00


Antti Petajisto, PhD, Head of Equities, Brooklyn Investment Group 

Antti Petajisto is a quantitative researcher and portfolio manager, focusing on systematic investment strategies and tax-efficient implementation.  

Antti has previously worked at hedge funds and asset managers like BlackRock, LMR Partners, and QuantPort, developing new alpha signals and managing long-short and long-only portfolios of equities in developed and emerging markets up to several billion dollars in assets. He is also a former finance professor at the Yale School of Management and NYU Stern School of Business, where he taught MBA courses on investments, portfolio management, and behavioural finance.  

Antti’s academic research has won numerous awards and has been frequently cited in the popular press, and it includes the invention of the active share concept for quantifying active portfolio management, performance evaluation of money managers, pricing inefficiencies in exchange-traded funds, and the price impact of passive indexing strategies.  

Antti has a Ph.D. in Finance from MIT Sloan School of Management and M.Sc. in Engineering Physics from the Helsinki University of Technology. 

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