Still, Thursday's setback highlights the challenges U.S. activist investors can face investing in countries that have different corporate governance structures, tax and other rules. Last month, for example, Elliott shifted part of its strategy in pushing for change at BHP Billiton Ltd. by proposing that the mining giant retain a main stock listing in Australia. Previously, it sought shareholder support for BHP to end its dual listing in Sydney and London in favor of a U.K.-only listing, but that plan met opposition by the Australian government.