London-based research firm Activist Insight agreed to buy Activist Shorts Research, a U.S. company that compiles information on public short-selling campaigns.

Activist Shorts had data on more than 800 campaigns by short sellers such as Citron Research, Carson Block’s Muddy Waters Capital LLC and Bill Ackman’s Pershing Square Capital Management LP, according to its website. Nick Arnott and Kerry Pogue, founders of Activist Insight, will lead the merged company, while Activist Shorts’s co-founder and president Adam Kommel will step down after helping with the transition. The size of the deal, completed last week, wasn’t disclosed.

Activist Insight, which focuses on shareholder activism across the globe, was founded in 2012, according to its website. It has offices both in London and New York. It has compiled about 1,300 profiles on activist investors and says its clients include investment banks, law firms, shareholder communications firms and institutional investors. Both Arnott and Pogue have previously worked at Preqin, a financial-information firm.

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