More than fifteen years after a global anti-bribery treaty was first entered into force, more than half of the current 41 nations that have signed and adopted that treaty are doing “little or nothing” to stop their companies from bribing foreign officials to illegally win or inflate contracts, an investigation by nonprofit Transparency International has found. Due to the stealth-like nature of corrupt international deals and clever blockades that nefarious deal-makers implement, the investigations required to get a prosecution are too complicated for many countries’ insufficient and ill-equipped law enforcement agencies.

Of the 34 member countries of the Organisation for Economic Co-operation and Development and seven nonmember countries that have presently adopted the OECD Anti-Bribery Convention treaty (first established on Dec. 17, 1997, and initially entered into force on Feb. 15, 1999), promising to criminalize, investigate and prosecute those individuals and companies that bribe public officials of other countries, only Germany, Switzerland, the U.K. and the U.S., representing about 23 percent of the world’s exports, are actively investigating and prosecuting companies allegedly involved in corruption, the report found

Twenty-two countries, representing more than a quarter of global trade, including Ireland and Japan, are reportedly doing little or nothing to stop bribery. Those failing altogether to investigate and prosecute foreign bribery include Japan, Russia, Spain, South Korea, Mexico, Brazil, Greece, Poland, Netherlands and others. Eight countries, including Sweden and France, have limited enforcement, and five, including Australia and Canada, show moderate enforcement efforts.

Corrupt international deals are increasingly sealed through middle companies with no assets or business operations, no physical address and whose owners are unknown even to authorities. And many countries’ law enforcement agencies lack the resources for these complicated investigations, and governments lack the political pressure or will to probe large companies.

The OECD recognizes that the convention that pushed countries to adopt anti-bribery laws is only the first step toward squeezing out bribery. “Now [the OECD] needs to make sure that enforcement authorities have all the support they need to counter the growing power of cross-border crime networks,” Transparency International chair Jose Ugaz told the Guardian.