After two decades in which most of the world embraced open investment policies, producing investment flows that grew at nearly twice the pace of global trade, some governments are putting up new barriers to foreign acquisitions.

In April, the Canadian government blocked the US group Alliant Techsystems from purchasing the space technology division of MacDonald Dettwiler – the first transaction ever blocked under the Investment Canada Act. That same month the Japanese government forbade The Children’s Investment Fund of the UK from increasing its stake in the electricity wholesaler J-Power, the first time it has blocked a foreign investment in a public company. Controversy led to Dubai investors pulling out from acquiring the Auckland airport; months later, the government of New Zealand blocked a Canadian pension fund’s proposed 40 per cent stake in the same airport.