Leaders have hailed the London meeting as the biggest demonstation of political will to tackle graft but critics say nothing has been done to expose international tax havens.
British Prime Minister David Cameron's conference got off to a shaky start with his unguarded reference to the participation of the "fantastically corrupt" Afghanistan and Nigeria.
But at the London summit, there was no downplaying the problem from the countries in question.
Nigerian President Muhammadu Buhari thanked Mr Cameron for his courage in mobilising the international community to tackle corruption, describing it as one of the greatest enemies of the era.
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"It runs completely counter to our values and also creates a system of patronage where the resources are shared out by a small elite while the majority are trapped in poverty. When it comes to tackling corruption the international community has unfortunately looked the other way for too long. We need to step up and tackle this evil."
The President of Afghanistan, Ashraf Ghani, cited figures showing that of the US $500 billion of drug money produced in his country over the past decade, roughly US $480 billion ended up in Europe.
"There's been no prosecution for this. People across the developing world are fed up. There is no obstacle to desirability from the perspective of the people - on the contrary. But the notion that there are elite deals - and elite deals, corrupt elite deals are essential to stability - has to be discarded."
Britain, France, the Netherlands, Nigeria and Afghanistan have pledged to set up public registers of true company ownership.
They'll also implement other measures to tackle issues ranging from property money-laundering to doping and match-fixing in sport.
David Cameron describes the agreement as the biggest demonstration of political will for many years to stamp out international graft.
"This means that everyone in the world will be able to see who really owns and controls each and every company in these countries. If you don't know who owns what, you can't stop people stealing from poor countries and hiding that stolen wealth in rich ones. If we want to tackle poverty, if we want to beat extremism, if we want to narrow the gap between the richest countries in the world and the poorest countries in the world, we have to tackle corruption. "
The President of Ghana, John Dramani Mahama, believes by working together, countries can improve their own corruption-fighting laws.
"Africa has its own peculiarity in terms of weak institutions. We are still building a lot of those democratic institutions and trying to strengthen them so that they bring a lot more integrity into our processes and that has been quite an uphill task."
United States Secretary of State John Kerry told the summit there is no doubt corruption is intensifying the threat of terrorsm across the globe.
"And the extremism that we see in the world today comes to no small degree from the utter exasperation that people have with the sense that the system is rigged. We see this anger manifesting itself in different forms in elections around the world including ours. People are angry and the anger's going to grow, unless we shut the doors and try to prove to people there's a fairness."
And the rise of technology is helping to expose un-fairness.
World Bank President Jim Yong Kim highlighted the effect of what he called "radical transparency" as a deterrent to corruption.
"Whether we like it or not, hackers are going to expose more and more - the Panama papers were a good example. So in that regard, since it will be forced on us anyway, we need to send a message to those who are benefiting from corruption that we're going to get to the bottom of this."
International Monetary Fund Director Christine Lagarde says anyone who is pro-growth must also be anti-corruption.
"There is a very strong link between corruption and lower growth, non-sustainable growth, lower revenues for the states, additional inflation, reduced appetite by foreign direct-investors, additional cost of financing for the country."
But even as summit participants applauded their efforts, protesters outside were demonstrating, saying there's still much further to go to make governments and big corporations accountable.
