Theoretically, the panamanian bank and trust company that these documents leaked from operated in such a capacity.
The real outrage here is that people are stunned to realize that it takes money to be a politician, and that there are costs to political moves, both financial and otherwise, and doubly stunned that thier leaders engage in such actions.
The line between graft and simple costs of international politics is a murky, ill defined one at best.
Take for instance, what all needs to happen to secure a trade relationship with China, and what is standard operating process to do business in china.
I am pretty sure that if the US govt, or any other western govt created a "grease up Chinese regulators" fund, it would be very noisome in the press. Nevermind that this is exactly what has to happen to do basically anything in China.
That's where all this talk of graft and corruption is coming from. Not everyone plays by the same rules, and where those rules dont quite line up, exceptions need to be made, and sometimes theres a good and compelling reason not to discuss those exceptions publicly.
Basically, One planet, Different countries, Different philosophies, Different governments. To make it work, compromises need to happen. Greasing up regulators in another country, AS THEY EXPECT TO BE, is one such thing. It sucks, but it's the truth.
It strikes me as hollow that these people are mad about their prime minister's financial holdings, and less about the reasons why he has to hold them.
To me, one flows natrually from the other. Fix the underlying issue, and the problem fixes itself.
(By this, I mean drawing world attention to campaign finance, to international trade agreement politics, and things of this matter, so that politicians dont have to have huge warchests of private wealth and private interests to successfully be valuable government agents that are able to accomplish the tasks mandated of them.)