The Panamanian law firm whose more than 11 million leaked documents known as the "Panama Papers" shed light on how the world's wealthy exploit financial secrecy to hide assets says it is closing at the end of March.

The data breach from the Mossack-Fonseca firm was published by an international consortium of journalists and shook the ranks of the rich and powerful.

The firm's Wednesday statement says that at one time it had offices in 40 countries and some 600 employees. But after the 2016 publication of so many secrets it has closed offices and pared its staff to about 50.

The International Consortium of Investigative Journalists shared the 2017 Pulitzer Prize for explanatory reporting with McClatchy and the Miami Herald for their reporting on the Panama Papers.

Then Energy Minister Konrad Mizzi and the Prime Minister's chief of staff Keith Schembri were mentioned in the Panama Papers original leak in April 2016.

They later admitted to having had two companies opened in Panama under the names Tillgate and Hearneville. The Maltese owner of a third comoany, called Egrant, is still not officially known. An investigation is ongoing after it was revealed that the owner is the PM's wife Michelle Muscat, a claim that the Muscats deny.