Meanwhile, President Obama has spoken out about the Panama Papers while urging Congress to close tax loopholes, known as “inversions,” in which U.S. corporations agree to be bought by foreign companies simply to avoid paying U.S. taxes. The Treasury Department has unveiled new regulations to try to limit this process. On Tuesday, Obama said that many in the United States were taking advantage of legal loopholes to avoid U.S. taxes.

President Barack Obama: “We’ve had another reminder, in this big dump of data coming out of Panama, that tax avoidance is a big global problem. It’s not unique to other countries, because, frankly, there are folks here in America who are taking advantage of the same stuff. A lot of it’s legal, but that’s exactly the problem. It’s not that they’re breaking the laws, it’s that the laws are so poorly designed that they allow people, if they’ve got enough lawyers and enough accountants, to wiggle out of responsibilities that ordinary citizens are having to abide by.”

Also on Tuesday, pharmaceutical giant Pfizer reportedly decided to abandon plans to merge with the Ireland-based drug maker Allergan, following the unveiling of the Treasury Department’s new rules. The deal would have allowed Pfizer to avoid billions in U.S. taxes and would have been one of the largest corporate inversions in U.S. history.