Thomas Catan is a “partner” in the controversial opposition research firm Fusion GPS. The firm is best known for its work on the “Steele Dossier,” a document produced under the sponsorship of persons associated with the Democratic National Committee filled with unverified information alleging substantial involvement between Russian government interests and the 2016 Presidential campaign of Donald Trump. 
Catan, a former journalist, joined the firm along with two other former Wall Street Journal colleagues. He also previously worked for the Financial Times and The Times (of London).
Thomas Catan is a research consultant and “partner” with the political opposition research group Fusion GPS, where he has worked since February 2014.  Before joining Fusion GPS, he worked for six years as a journalist for the Wall Street Journal. He reported on international economics, political expenditures, investigative projects, and legal affairs. 
Before working at the Journal, Catan was a correspondent for the Financial Times for seven years, where he was an investigative reporter and an Argentina correspondent. He previously worked for London newspaper The Times as a correspondent in Spain. 
Steele Dossier Controversy
Catan and fellow Wall Street Journal alumnus Peter Fritsch both invoked their Fifth Amendment right against self-incrimination in front of the House Select Committee on Intelligence in October 2017 during a closed-door session. They were asked who paid for the dossier written by former British spy Christopher Steele, filled with unverifiable information alleging whether President Donald Trump conspired with Russians to meddle in the 2016 presidential election. 
The lawyer for the two, Joshua Levy, said his clients only cooperate with “serious” investigations and said the “Trump cabal has carried out a campaign to demonize our client for having been tied to the Trump dossier.” 
Levy also said of his two clients after the hearing, “No American should have to experience the indignity that occurred today … No American should be required to appear before a congressional committee just to invoke his constitutional privileges.”