In August 2009, France and Switzerland amended their tax treaty. The new treaty stated that the two countries would from now on exchange upon request all information necessary for tax enforcement, including bank information otherwise protected by Swiss bank secrecy laws. In the following months, one of France’s richest persons and her wealth manager were taped discussing what to do with two undeclared Swiss bank accounts, worth $160 millions. After a visit to Switzerland, the wealth manager concluded that keeping the funds in Swiss banks or bringing them back to France would be too risky. He suggested that the funds be transferred to Hong-Kong, Singapore, or Uruguay, three tax havens which had not committed to exchange information with France. After the tapes were made public, they were widely commented in French newspapers and eventually the funds were repatriated to France.
The amendment to the French-Swiss tax treaty was part of a global initiative to combat tax evasion. Since the end of the 1990s, the OECD has encouraged tax havens to exchange information with other countries on the basis of bilateral tax treaties, but until
2008 most tax havens declined to sign such treaties. During the ﬁnancial crisis, the ﬁght against tax evasion became a political priority in rich countries and the pressure on tax havens mounted. At the summit held in April 2009, G20 countries urged tax havens to sign at least 12 treaties under the threat of economic sanctions. Between the summit and the end of 2009, tax havens signed more than 300 treaties. This is the largest coordinated action against tax evasion the world has ever seen.
The eﬀectiveness of the G20 tax haven crackdown is highly contested. A positive view asserts that treaties signiﬁcantly raise the probability of detecting tax evasion and greatly improve tax collection (OECD, 2011). According to policy makers, “the era of bank secrecy is over” (G20, 2009). A negative view, on the contrary, asserts that the G20 initiative leaves considerable scope for bank secrecy and brings negligible beneﬁts (Shaxson and Christensen, 2011).