based Abraaj Capital has held talks with Egypt's Citadel Capital with a view to possibly buying a stake in the rival private equity firm, a source familiar with the matter said. The talks are still at a very preliminary stage and no formal offer has been made, said the source, who did not want to be identified. Citadel shares were up 3.5 percent at 5.85 pounds at 1042 GMT after earlier rising as high as 6.16 pounds in a flat market. Abraaj manages assets of over $6 billion and Citadel manages assets of $4 billion. Last week traders cited market talk that an unnamed Dubai-based firm may be eyeing a stake in Citadel, which pushed up Citadel's share price. Citadel said at the time it had not received any direct acquisition offer. Citadel Managing Director Ahmed El Houssieny declined to comment and Abraaj Capital's Egypt Vice President Hisham Moussa said he was not aware of the talks. A spokesman for Abraaj Capital in Dubai declined to comment. Abraaj Capital manages assets of over $6 billion and Citadel manages assets of $4 billion. Last week, shares rose as much as 20 percent on speculation that Citadel had received an offer for its shares at 8 Egyptian pounds.