Chinese firms which have relocated operations to the region in a bid to seek lower tariffs on their US exports, as well as Southeast Asian businesses across the supply chain, are feeling the pinch from the 40 per cent US transshipment levy.   HANOI: In recent years, Chinese firm Huashuo Plastics has moved a significant proportion of its operations from Guangdong in southeastern China to Hai Phong in northern Vietnam. Before 2016, almost all of its production was focused in Dongguan - an