Individuals and/or corporate entities can find it attractive to move themselves to areas with reduced or nil taxation levels. This creates a situation of tax competition among governments. Different jurisdictions tend to be havens for different types of taxes, and for different categories of people and/or companies.
States that are sovereign or self-governing under international law have theoretically unlimited powers to enact tax laws affecting their territories, unless limited by previous international treaties.
There are several definitions of tax havens. The Economist has tentatively adopted the description by Geoffrey Colin Powell (former economic adviser to Jersey): "What ... identifies an area as a tax haven is the existence of a composite tax structure established deliberately to take advantage of, and exploit, a worldwide demand for opportunities to engage in tax avoidance." The Economist points out that this definition would still exclude a number of jurisdictions traditionally thought of as tax havens. Similarly, others have suggested that any country which modifies its tax laws to attract foreign capital could be considered a tax haven. According to other definitions, the central feature of a haven is that its laws and other measures can be used to evade or avoid the tax laws or regulations of other jurisdictions.
In its December 2008 report on the use of tax havens by American corporations, the U.S. Government Accountability Office was unable to find a satisfactory definition of a tax haven but regarded the following characteristics as indicative of a tax haven:
The use of differing tax laws between two or more countries to try to mitigate tax liability is probably as old as taxation itself. In Ancient Greece, some of the Greek Islands were used as depositories by the sea traders of the era to place their foreign goods to thus avoid the two-percent tax imposed by the city-state of Athens on imported goods. It is sometimes suggested that the practice first reached prominence through the avoidance of the Cinque ports and later the staple ports in the twelfth and fourteenth centuries respectively. In 1721, American colonies traded from Latin America to avoid British taxes.
Various countries claim to be the oldest tax haven in the world. For example, the Channel Islands claim their tax independence dating as far back as Norman Conquest, while the Isle of Man claims to trace its fiscal independence to even earlier times. Nonetheless, the modern concept of a tax haven is generally accepted to have emerged at an uncertain point in the immediate aftermath of World War I. Bermuda sometimes optimistically claims to have been the first tax haven based upon the creation of the first offshore companies legislation in 1935 by the newly created law firm of Conyers Dill & Pearman. However, the Bermudian claim is debatable when compared against the enactment of a Trust Law by Liechtenstein in 1926 to attract offshore capital.
Most economic commentators suggest that the first "true" tax haven was Switzerland, followed closely by Liechtenstein. Swiss banks had long been a capital haven for people fleeing social upheaval in Russia, Germany, South America and elsewhere. However, in the early part of the twentieth century, in the years immediately following World War I, many European governments raised taxes sharply to help pay for reconstruction efforts following the devastation of World War I. By and large, Switzerland, having remained neutral during the Great War, avoided these additional infrastructure costs and was consequently able to maintain a low level of taxes. As a result, there was a considerable influx of capital into the country for tax related reasons. It is difficult, nonetheless, to pinpoint a single event or precise date which clearly identifies the emergence of the modern tax haven.
Until the 1950s, tax havens were used to avoid personal taxation but since then jurisdictions have come to focus on attracting companies with low or no corporate tax. Centres which focus on providing financial services to corporations rather than private wealth management are more often known as offshore financial centres.
This strategy generally relied on double taxation treaties between large jurisdictions and the tax haven, allowing corporations to structure group ownership through the smaller jurisdiction to reduce tax liability. Although some of these double tax treaties survive, in the 1970s, most major countries began repealing their double taxation treaties with micro-states to prevent corporate tax leakage in this manner.
In the early to mid-1980s, most tax havens changed the focus of their legislation to create corporate vehicles which were "ring-fenced" and exempt from local taxation (although they usually could not trade locally either). These vehicles were usually called "exempt companies" or "International Business Corporations". However, in the late 1990s and early 2000s, the OECD began a series of initiatives aimed at tax havens to curb the abuse of what the OECD referred to as "unfair tax competition". Under pressure from the OECD, most major tax havens repealed their laws permitting these ring-fenced vehicles to be incorporated, but concurrently they amended their tax laws so that a company which did not actually trade within the jurisdiction would not accrue any local tax liability.
Most tax havens have a double monetary control system which distinguish residents from non-resident as well as foreign currency from the domestic one. In general, residents are subject to monetary controls but not non-residents. A company, belonging to a non-resident, when trading overseas is seen as non-resident in terms of exchange control.
It is possible for a foreigner to create a company in a tax haven to trade internationally; the company’s operations will not be subject to exchange controls as long as it uses foreign currency to trade outside the tax haven.
At the risk of gross oversimplification, it can be said that the advantages of tax havens are viewed in four principal contexts:
The Organisation for Economic Co-operation and Development (OECD) identifies three key factors in considering whether a jurisdiction is a tax haven:
However the OECD found that its definition caught certain aspects of its members' tax systems (some countries have low or zero taxes for certain favored groups). Its later work has therefore focused on the single aspect of information exchange. This is generally thought to be an inadequate definition of a tax haven, but is politically expedient because it includes the small tax havens (with little power in the international political arena) but exempts the powerful countries with tax haven aspects such as the USA and UK.
In deciding whether or not a jurisdiction is a tax haven, the first factor to look at is whether there are no or nominal taxes. If this is the case, the other two factors – whether or not there is an exchange of information and transparency – must be analyzed. Having no or nominal taxes is not sufficient, by itself, to characterize a jurisdiction as a tax haven. The OECD recognizes that every jurisdiction has a right to determine whether to impose direct taxes and, if so, to determine the appropriate tax rate.
To avoid tax competition, many high tax jurisdictions have enacted legislation to counter the tax sheltering potential of tax havens. Generally, such legislation tends to operate in one of five ways:
However, many jurisdictions employ blunter rules. For example, in France securities regulations are such that it is not possible to have a public bond issue through a company incorporated in a tax haven.
Also becoming increasingly popular is "forced disclosure" of tax mitigation schemes. Broadly, these involve the revenue authorities compelling tax advisors to reveal details of the scheme, so that the loopholes can be closed during the following tax year, usually by one of the five methods indicated above. Although not specifically aimed at tax havens, given that so many tax mitigation schemes involve the use of offshore structures, the effect is much the same.
Anti-avoidance came to prominence in 2010/2011 as NGOs and politicians in the leading economies looked for convenient scapegoats for their governments' spending cuts. The International Financial Centres Forum (IFC Forum) has asked for a balanced debate on the issue of tax avoidance and an understanding of the role that the tax neutrality of small international financial centres plays in the global economy.
There are several reasons for a nation to become a tax haven. Some nations may find they do not need to charge as much as some industrialized countries in order for them to be earning sufficient income for their annual budgets. Some may offer a lower tax rate to larger corporations, in exchange for the companies locating a division of their parent company in the host country and employing some of the local population. Other domiciles find this is a way to encourage conglomerates from industrialized nations to transfer needed skills to the local population. Still yet, some countries simply find it costly to compete in many other sectors with industrialized nations and have found a low tax rate mixed with a little self-promotion can go a long way to attracting foreign companies.
Many industrialized countries claim that tax havens act unfairly by reducing tax revenue which would otherwise be theirs. Various pressure groups also claim that money launderers also use tax havens extensively, although extensive financial and KYC regulations in tax havens can actually make money laundering more difficult than in large onshore financial centers with significantly higher volumes of transactions, such as New York City or London. In 2000 the Financial Action Task Force published what came to be known as the "FATF Blacklist" of countries which were perceived to be uncooperative in relation to money laundering; although several tax havens have appeared on the list from time to time (including key jurisdictions such as the Cayman Islands, Bahamas and Liechtenstein), no offshore jurisdictions appear on the list at this time.
A very interesting incentive was Inland Revenue and HM Customs and Excise agreeing to sell more than 600 of their building stock to a firm in a tax haven. The sell-off, was made to Bermuda based Mapeley Steps Ltd in 2001.
See also: List of offshore financial centres and Tax rates around the world. The U.S. National Bureau of Economic Research has suggested that roughly 15% of countries in the world are tax havens, that these countries tend to be small and affluent, and that better governed and regulated countries are more likely to become tax havens, and are more likely to be successful if they become tax havens.
No two commentators can generally agree on a "list of tax havens", but the following countries are commonly cited as falling within the "classic" perception of a sovereign tax haven.
Non-sovereign jurisdictions commonly labelled as tax havens include:
Some tax havens including some of the ones listed above do charge income tax as well as other taxes such as capital gains, inheritance tax, and so forth. Criteria distinguishing a taxpayer from a non-taxpayer can include citizenship and residency and source of income.
While incomplete, and with the limitations discussed below, the available statistics nonetheless indicate that offshore banking is a very sizeable activity. IMF calculations based on BIS data suggest that for selected OFCs (Offshore Financial Centres), on balance sheet OFC cross-border assets reached a level of US$4.6 trillion at end-June 1999 (about 50 percent of total cross-border assets), of which US$0.9 trillion in the Caribbean, US$1 trillion in Asia, and most of the remaining US$2.7 trillion accounted for by the IFCs (International Financial Centers), namely London, the U.S. IBFs, and the JOM (Japanese Offshore Market).
A 2006 academic paper indicated that: "in 1999, 59% of U.S. firms with significant foreign operations had affiliates in tax haven countries", although they did not define "significant" for this purpose.
A January 2009 Government Accountability Office (GAO) report said that the GAO had determined that 83 of the 100 largest U.S. publicly traded corporations and 63 of the 100 largest contractors for the U.S. federal government were maintaining subsidiaries in countries generally considered havens for avoiding taxes. The GAO did not review the companies' transactions to independently verify that the subsidiaries helped the companies reduce their tax burden, but said only that historically the purpose of such subsidiaries is to cut tax costs.
Currently the Caribbean Banking Centers which include Bahamas, Bermuda, Cayman Islands, Netherlands Antilles, and Panama hold almost two trillion dollars in United States debt.
In October 2009 research commissioned from Deloitte for the Foot Review of British Offshore Financial Centres indicated that much less tax had been lost to tax havens than previously had been thought. The report indicated "We estimate the total UK corporation tax potentially lost to avoidance activities to be up to £2 billion per annum, although it could be much lower." The report also dissected an earlier report by the TUC, which had concluded that tax avoidance by the 50 largest companies in the FTSE 100 was depriving the UK Treasury of approximately £11.8 billion. The TUC's analysis had looked at the reported profits of the companies and the amount of tax paid, which created a gap in tax revenues which was mostly due to differences in the accounting treatment of profit for taxation purposes, which were intended under the UK's tax rules. The report also stressed that British Crown Dependencies make a "significant contribution to the liquidity of the UK market". In the second quarter of 2009, they provided net funds to banks in the UK totalling $323 billion (£195 billion), of which $218 billion came from Jersey, $74 billion from Guernsey and $40 billion from the Isle of Man.
Tax Justice Network, an anti-tax haven pressure group, suggests that global tax revenue lost to tax havens exceeds US$255 billion per year, although those figures are not widely accepted. Estimates by the OECD suggest that by 2007 capital held offshore amounts to somewhere between US$5 trillion and US$7 trillion, making up approximately 6–8% of total global investments under management. Of this, approximately US$1.4 trillion is estimate to be held in the Cayman Islands alone.
The Center for Freedom and Prosperity disputes claims about forgone tax revenue. Academic researchers also have found that tax havens actually boost prosperity in neighboring jurisdictions by creating tax-efficient platforms for economic activity – much of which would not occur if subject to onerous taxes if controlled by a domestic entity. Some support for this is found in academic studies which suggest that the tax elasticity of investment is approximately −0.6.
The Foreign Account Tax Compliance Act (FATCA) was initially introduced to target those who evade paying U.S. taxes by hiding assets in undisclosed foreign bank accounts. With the strong backing of the Obama Administration, Congress quickly drafted the FATCA legislation and slipped it into the vaguely related Hiring Incentives to Restore Employment Act (HIRE) signed into law by President Obama in March 2010.
An unintended but serious problem with FATCA is that compliance is so expensive for non-US banks that they are refusing to serve American investors.
FATCA requires foreign financial institutions (FFI) of broad scope – banks, stock brokers, hedge funds, pension funds, insurance companies, trusts – to report directly to the IRS all clients who are U.S. Persons. Starting January 1, 2013 (later delayed to 2014), FATCA will require FFIs to provide annual reports to the Internal RevenueService (IRS) on the name and address of each U.S. client, as well as the largest account balance in the year and total debits and credits of any account owned by a U.S. person. If an institution does not comply, the U.S. will impose a 30% withholding tax on all its transactions concerning U.S. securities, including the proceeds of sale of securities.
In addition, FATCA requires any foreign company not listed on a stock exchange or any foreign partnership which has 10% U.S. ownership to report to the IRS the names and tax I.D. number (TIN) of any U.S. owner.
FATCA also requires U.S. citizens and green card holders who have foreign financial assets in excess of $50,000 to complete a new Form 8938 to be filed with the 1040 tax return, starting with fiscal year 2011 (later delayed to 2012). 
The delay is indicative of a controversy over the feasibility of implementing the legislation as evidenced in this paper from the renowned Peterson Institute for International Economics. 
In January 2009, Peer Steinbrück, the German financial minister, announced a plan to amend fiscal laws. New regulations would disallow that payments to companies in certain countries that shield money from disclosure rules be declared as operative expenses. The effect of this would make banking in such states unattractive and expensive.
See main article: 2008 Liechtenstein tax affair.
In February 2008, Germany announced that it had paid €4.2 million to Heinrich Kieber, a former data archivist of LGT Treuhand, a Liechtenstein bank, for a list of 1,250 customers of the bank and their accounts' details. Investigations and arrests followed relating to charges of illegal tax evasion. The German authorities shared the data with U.S. tax authorities, but the British government paid a further £100,000 for the same data. Other governments, notably Denmark and Sweden, refused to pay for the information regarding it as stolen property. The Liechtenstein authorities subsequently accused the German authorities of espionage.
However, regardless of whether unlawful tax evasion was being engaged in, the incident has fuelled the perception amongst European governments and press that tax havens provide facilities shrouded in secrecy designed to facilitate unlawful tax evasion, rather than legitimate tax planning and legal tax mitigation schemes. This in turn has led to a call for "crackdowns" on tax havens. Whether the calls for such a crackdown are mere posturing or lead to more definitive activity by mainstream economies to restrict access to tax havens is yet to be seen. No definitive announcements or proposals have yet been made by the European Union or governments of the member states.
At the London G20 summit on 2 April 2009, G20 countries agreed to define a blacklist for tax havens, to be segmented according to a four-tier system, based on compliance with an "internationally agreed tax standard." The list as per April 2nd of 2009 can be viewed on the OECD Data  After a great progress the four tiers are now:
Those countries in the bottom tier were initially classified as being 'non-cooperative tax havens'. Uruguay was initially classified as being uncooperative. However, upon appeal the OECD stated that it did meet tax transparency rules and thus moved it up. The Philippines took steps to remove itself from the blacklist and Malaysian Prime Minister Najib Razak had suggested earlier that Malaysia should not be in the bottom tier. On April 7, 2009, the OECD, through its chief Angel Gurria, announced that Costa Rica, Malaysia, the Philippines and Uruguay have been removed from the blacklist after they had made "a full commitment to exchange information to the OECD standards."
Despite calls from French President Nicolas Sarkozy for Hong Kong and Macau to be included separately from China on the list, they are as of yet not included independently, although it is expected that they will be added at a later date.
Government response to the crackdown has been broadly supportive, although not universal. Luxembourg Prime Minister Jean-Claude Juncker has criticised the list, stating that it has "no credibility", for failing to include various states of the U.S.A. which provide incorporation infrastructure which are indistinguishable from the aspects of pure tax havens to which the G20 object.
In November 2009 Sir Michael Foot delivered a report on the British Crown Dependencies and Overseas Territories for HM Treasury. The report indicated that whilst many of the territories "had a good story to tell", others needed to improve in detection and prevention of financial crime. It also stressed the view that narrow tax bases presented long term strategic risks, and that the economies should seek to diversify and broaden their own tax bases. The report also indicated that tax revenue lost by the United Kingdom government appeared to be much smaller than had previously estimated (see above under Lost tax revenue), and also stressed the importance of the liquidity provided by the territories to the United Kingdom. The Crown Dependencies and Overseas Territories broadly welcomed the report, but the pressure group Tax Justice Network, unhappy with the findings, commented "[a] weak man, born to be an apologist, has delivered a weak report."