This paper explores tax arbitrage incentives and behaviours in OECD countries, and their implications for tax systems more broadly. It focuses on how OECD tax systems might encourage business owners, in particular owners of unincorporated businesses and owner-managers of closely held incorporated businesses, to minimise their tax burdens through tax arbitrage. The paper finds that tax incentives to incorporate and earn capital income through corporations have increased in the last two decades. It shows that there has been an increase in incorporated businesses in many OECD countries, which has been partly driven by tax factors. The paper also finds that, in many countries, a combination of tax system features – related to corporate, dividend, capital gains, gift and inheritance taxation – provide particularly strong incentives to retain earnings inside corporations.