This article develops a micro-level understanding of informal work (IW) by exploring the legitimising factors which business owners exercise to provide the rationale for engaging in IW. Using the lens of nudge theory, originating from behavioural economics, we show how IW becomes legitimised through nudging. Empirically, we explore the lived experience of service sector business owners who engage in IW practices in the East Midlands, UK. The findings uncover how the business owners’ context is shaped through exposure to various IW arrangements early in their working life; we also reveal a range of actors who actively shape these arrangements for embracing IW while delegitimising formal work. We present the factors that condition the beliefs and embed the understanding that IW is legitimate for the individual business owners, thus highlighting an important and emergent context for future studies in the realm of IW.