Standard arguments in comparative political economy predict that protected labour market insiders oppose redistribution to poorer labour market outsiders, often working in the informal sector. Opposition from insiders may thus prevent the expansion of non-contributory social policies that mitigate poverty in developing countries around the world. In contrast, this paper develops and tests the argument that not all formal (insider) workers uniformly oppose redistribution. Drawing on theories of social insurance, I argue that risk concerns become more salient than redistributive ones among economically vulnerable insiders. As a result, insiders exposed to high levels of economic insecurity support increased redistribution to outsiders. I examine the empirical implications using a survey experiment for a nationally representative sample of 800 respondents in cities of 10000 or more in Argentina, a country with strict employment protection, high informality and weak social insurance. The findings show that low-skilled insiders primed about the risk of job loss more strongly support redistribution to outsiders. These results provide microfoundations that help to explain the growth of non-contributory social policies in the developing world over the last two decades.