FRANKFURT (Reuters) - Switzerland and the United States are the most secretive major financial centers in the world, according to a global ranking compiled by a group campaigning for more transparency.

A Swiss flag is pictured during the sunrise on the Commercial and Financial District in Geneva, Switzerland, November 23, 2017. REUTERS/Denis Balibouse

The Tax Justice Network’s study found Switzerland to be the “global capital of bank secrecy” while it placed the United States in second place because its share of global offshore financial services has increased steadily.

The study, which is published every two years, checks countries using several criteria including how much information they provide about the ownership of trusts or foundations and the degree to which they respect money-laundering rules.

The analysis looked at 110 countries.

John Christensen, director of the network, said the study showed that while some financial centers said they were becoming more transparent, the amount of information they released depended on who requested it.

“Rich, Western countries get information but poorer countries in Africa do not,” he said, adding that secrecy enabled money laundering and theft.

“You have tax evasion going on every level. We are seeing the systematic looting of countries,” said Christensen. “The sums involved are enormous.”

Other countries that were ranked among the most significant secretive centers included the Cayman Islands, Luxembourg and Germany. Hong Kong and Singapore were also among the top 10.

The study adds to a wider debate about the use of such centers after the publication of the Panama Papers, which showed that some companies set up in tax havens may have been used for money laundering, arms and drug deals as well as tax evasion.

That embarrassed leaders worldwide who had interests tied to secretive business concerns.

Switzerland, the world’s largest center for overseas wealth, will gradually dismantle bank secrecy this year when it begins sending information about its customers’ accounts to foreign tax agencies.

The Alpine country’s multi-trillion-dollar financial industry has, however, sought safeguards to protect against misuse of this information, a step critics said was a back-door attempt to continue with secrecy.

The Swiss government is now considering how wide such protection should be as it further rolls back bank secrecy.

Pressure on Switzerland built after a U.S.-led crackdown starting in 2008 publicized practices used by its bankers to keep money hidden from tax authorities, from smuggling diamonds in toothpaste tubes to hiding documents in the pages of Sports Illustrated.

The United States Treasury did not respond immediately to a request for comment.