Rudy Giuliani, the former mayor of New York, on Monday provided further evidence that he is stepping up his presidential campaign for 2008 when he sold his boutique investment bank, Giuliani Capital Partners, addressing concerns about potential conflicts of interest and adding to his warchest of campaign financing.

The terms of the sale to Macquarie Group, an Australian financial group, were not disclosed but analysts said that Giuliani Capital Advisors could be worth as much as $100m. It represents a large chunk of Mr Giuliani’s business interests, which he began building in early 2002, shortly after leaving his post as mayor.