Labour unions are rallying across South Korea after Samsung Electronics caved in to protests and agreed to hand out bonuses of more than US$400,000 to some of its employees.Just this week, assembly-line workers at Hyundai Motor staged a three-day partial strike as they seek up to 30 per cent of consolidated profit to be set aside for bonuses.Meanwhile, unions at HD Hyundai Heavy Industries and telecoms operator LG Uplus want payouts equivalent to at least 30 per cent of operating profit, while workers at Hanwha Aerospace and HD Hyundai Electric want to scrap bonus caps altogether.In tech, thousands of employees at Kakao, which operates South Korea’s largest messaging service, went on strike for the first time last month, demanding that up to 15 per cent of operating profit be allocated for bonuses. The union at Naver, the country’s top search engine provider, is forming a coalition with counterparts at multiple affiliates to strengthen their negotiating power.A currency dealer walks in front of an electronic board displaying SK Hynix and Samsung Electronics stock prices and the Korea stock index at the dealing room of a bank in Seoul on July 16. Photo: ReutersWhat began with workers calling for Samsung and SK Hynix, the nation’s two biggest chipmakers, to share the banner profits they are reaping from the artificial intelligence boom is spilling over to industries that have little to do with AI. It is a reminder of the risks investors face in a country that has historically had one of the most militant labour union presences in the region.