Rewriting History

36 Pages Posted: 13 Nov 2008

See all articles by Alexander Ljungqvist

Alexander Ljungqvist

Centre for Economic Policy Research (CEPR); Stockholm School of Economics; European Corporate Governance Institute (ECGI); Research Institute of Industrial Economics (IFN)

Christopher J. Malloy

Harvard Business School; National Bureau of Economic Research (NBER); Arrowstreet Capital, LP

Felicia C. Marston

University of Virginia - McIntire School of Commerce

Multiple version iconThere are 2 versions of this paper

Date Written: April 2008

Abstract

We document widespread ex post changes to the historical contents of the I/B/E/S analyst stock recommendations database. Across a sequence of seven downloads of the entire I/B/E/S recommendations database, obtained between 2000 and 2007, we find that between 6,594 (1.6%) and 97,579 (21.7%) of matched observations are different from one download to the next. The changes, which include alterations of recommendation levels, additions and deletions of records, and removal of analyst names, are non-random in nature: They cluster by analyst reputation, brokerage firm size and status, and recommendation boldness. The changes have a large and significant impact on the classification of trading signals and back-tests of three stylized facts: The profitability of trading signals, the profitability of changes in consensus recommendations, and persistence in individual analyst stock-picking ability.

Keywords: Security analysts, Stock recommendations, Global Settlement, Stock-picking ability, Forensic finance

Suggested Citation

Ljungqvist, Alexander and Ljungqvist, Alexander and Malloy, Christopher J. and Marston, Felicia C., Rewriting History (April 2008). NYU Working Paper No. FIN-06-004, Available at SSRN: https://ssrn.com/abstract=1300762

Alexander Ljungqvist (Contact Author)

Centre for Economic Policy Research (CEPR)

London
United Kingdom

Stockholm School of Economics ( email )

111 60 Stockholm
Sweden

European Corporate Governance Institute (ECGI)

c/o the Royal Academies of Belgium
Rue Ducale 1 Hertogsstraat
1000 Brussels
Belgium

Research Institute of Industrial Economics (IFN) ( email )

Box 55665
Grevgatan 34, 2nd floor
Stockholm, SE-102 15
Sweden

Christopher J. Malloy

Harvard Business School ( email )

Soldiers Field Road
Baker Library 277
Boston, MA 02163
United States
617-495-4383 (Phone)

National Bureau of Economic Research (NBER) ( email )

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

Arrowstreet Capital, LP ( email )

44 Brattle St., 5th Floor
Cambridge, MA 02138
United States

Felicia C. Marston

University of Virginia - McIntire School of Commerce ( email )

P.O. Box 400173
Charlottesville, VA 22904-4173
United States
804-924-1417 (Phone)

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