The role requires Blair to give a small number of geopolitical talks to the firm’s executives.
The former Labour leader’s appointment is surprising, given that Lansdowne co-founder Paul Ruddock and fund manager David Craigen both donate to the Conservative Party.
Blair is not taking on an advisory role at Lansdowne Partners, sources said, although it is believed he could do eventually. No one from Lansdowne was available to comment.
Lansdowne made millions of pounds by shorting banking stocks such as Barclays and Anglo Irish Bank during the crisis and then buying back into financials near the bottom of the market.
As of June 2009, it ran $11.9bn (£7.31bn) in assets, making it Europe’s fourth-largest hedge fund firm, according to EuroHedge data.
Several hedge funds have hired well-known politicians to help them better understand international politics.