Double Irish in the context of Put on the green jersey

Corporate haven, corporate tax haven, or multinational tax haven is used to describe a jurisdiction that multinational corporations find attractive for establishing subsidiaries or incorporation of regional or main company headquarters, mostly due to favourable tax regimes (not just the headline tax rate), and/or favourable secrecy laws (such as the avoidance of regulations or disclosure of tax schemes), and/or favourable regulatory regimes (such as weak data-protection or employment laws).

Unlike traditional tax havens, modern corporate tax havens reject they have anything to do with near-zero effective tax rates, due to their need to encourage jurisdictions to enter into bilateral tax treaties that accept the haven's base erosion and profit shifting (BEPS) tools. CORPNET show each corporate tax haven is strongly connected with specific traditional tax havens (via additional BEPS tool "backdoors" like the double Irish, the Dutch sandwich, and single malt). Corporate tax havens promote themselves as "knowledge economies", and intellectual property (IP) as a "new economy" asset, rather than a tax management tool, which is encoded into their statute books as their primary BEPS tool. This perceived respectability encourages corporates to use these International Financial Centres (IFCs) as regional headquarters (i.e. Google, Apple, and Facebook use Ireland in EMEA over Luxembourg, and Singapore in APAC over Hong Kong/Taiwan).

Ireland has been labelled as a corporate tax haven in multiple financial reports, an allegation which the state has rejected in response. Ireland is on all academic tax haven lists, including the § Leaders in tax haven research, and tax NGOs. Ireland does not meet the 1998 OECD definition of a tax haven, but no OECD member, including Switzerland, ever met this definition; only Trinidad & Tobago met it in 2017. Similarly, no EU–28 country is amongst the 64 listed in the 2017 EU tax haven blacklist and greylist. In September 2016, Brazil became the first G20 country to "blacklist" Ireland as a tax haven.

Ireland's base erosion and profit shifting (BEPS) tools give some foreign corporates § Effective tax rates of 0% to 2.5% on global profits re-routed to Ireland via their tax treaty network. Ireland's aggregate § Effective tax rates for foreign corporates is 2.2–4.5%. Ireland's BEPS tools are the world's largest BEPS flows, exceed the entire Caribbean system, and artificially inflate the US–EU trade deficit. Ireland's tax-free QIAIF & L–QIAIF regimes, and Section 110 SPVs, enable foreign investors to avoid Irish taxes on Irish assets, and can be combined with Irish BEPS tools to create confidential routes out of the Irish corporate tax system. As these structures are OECD–whitelisted, Ireland's laws and regulations allow the use of data protection and data privacy provisions, and opt-outs from filing of public accounts, to obscure their effects. There is arguable evidence that Ireland acts as a § Captured state, fostering tax strategies.

Ireland's Corporate Tax System is a central component of Ireland's economy. In 2016–17, foreign firms paid 80% of Irish corporate tax, employed 25% of the Irish labour force (paid 50% of Irish salary tax), and created 57% of Irish OECD non-farm value-add. As of 2017, 25 of the top 50 Irish firms were U.S.–controlled businesses, representing 70% of the revenue of the top 50 Irish firms. By 2018, Ireland had received the most U.S. § Corporate tax inversions in history, and Apple was over one–fifth of Irish GDP. Academics rank Ireland as the largest tax haven; larger than the Caribbean tax haven system.

Ireland's "headline" corporation tax rate is 12.5%, however, foreign multinationals pay an aggregate § Effective tax rate (ETR) of 2.2–4.5% on global profits "shifted" to Ireland, via Ireland's global network of bilateral tax treaties. These lower effective tax rates are achieved by a complex set of Irish base erosion and profit shifting ("BEPS") tools which handle the largest BEPS flows in the world (e.g. the Double Irish as used by Google and Facebook, the Single Malt as used by Microsoft and Allergan, and Capital Allowances for Intangible Assets as used by Accenture, and by Apple post Q1 2015).

Dutch Sandwich is a base erosion and profit shifting (BEPS) corporate tax tool, used mostly by U.S. multinationals to avoid incurring European Union withholding taxes on untaxed profits as they were being moved to non-EU tax havens (such as the Bermuda black hole). These untaxed profits could have originated from within the EU, or from outside the EU, but in most cases were routed to major EU corporate-focused tax havens, such as Ireland and Luxembourg, by the use of other BEPS tools. The Dutch Sandwich was often used with Irish BEPS tools such as the Double Irish, the Single Malt and the Capital Allowances for Intangible Assets ("CAIA") tools. In 2010, Ireland changed its tax-code to enable Irish BEPS tools to avoid such withholding taxes without needing a Dutch Sandwich.