THE NEW YORK TIMES

By BARRY MEIER

A version of this article appeared in print on July 8, 2010, on page A1 of the New York edition.

Transocean is the world’s largest offshore drilling company, but until its Deepwater Horizon rig exploded in the Gulf of Mexico in April, few Americans outside the energy business had heard of it. It is well known, however, in a number of other countries — for testing local laws and regulations.

Human rights advocates have called for an investigation into Transocean’s recent dealings in Myanmar. They cite its involvement in a drilling project that apparently included a company that is suspected of having ties to two men accused of laundering money for Myanmar’s repressive government, which is under United States trade sanctions.

Transocean has disclosed in Securities and Exchange Commission filings that its drilling equipment was shipped by a forwarder through Iran and that until last year it held a stake in a company that did business in Syria. The State Department says Syria and Iran sponsor terrorism.

In Norway, Transocean is the subject of a criminal investigation into possible tax fraud. The company has said in S.E.C. filings that Norwegian officials could assess it about $840 million in taxes and penalties. The filings also said that a final ruling against Transocean could have a “material impact” on the company, which has suffered a drop in its stock price of more than 40 percent since the Gulf of Mexico incident.

And in the United States, a federal bankruptcy judge recently found that one of Transocean’s merger partners had repeatedly abused the legal system to try to avoid potential liability in a pollution case in Louisiana. Transocean is also the target of tax inquiries in the United States and Brazil.

Transocean declined though an outside spokesman to make company officials available for comment. The company said in a statement that it had always acted appropriately and believed that it would prevail in any investigations.

It is not unusual for large multinational companies like Transocean to find themselves in legal or tax controversies around the world and Transocean has noted the issues that face it in public filings. The company’s most significant safety problem overseas involved a 2007 episode in which eight people died off the coast of Scotland when a support vessel capsized while towing a huge chain used to position a Transocean rig. A Norwegian board of inquiry found that missteps by several parties, including Transocean and the support vessel’s owner, had contributed to the incident.

But the company’s practices in the United States and abroad have come under new scrutiny since the oil spill in the gulf. Last week, the chairman of the Senate Finance Committee, Max Baucus, Democrat of Montana, said that the panel would investigate whether Transocean had used its corporate base in Switzerland to exploit United States tax laws.

In its dealings with lawmakers, Transocean has stood its ground. Last month, in response to a demand that Transocean delay a planned distribution to shareholders of $1 billion in dividends, the company declared that paying the dividend “in no way affects Transocean’s ability to meet it legal obligations.”

Transocean has largely blamed BP, the well’s operator, for the spill, describing it as a company that took shortcuts on safety. Transocean has had a long relationship with BP, and for the last two years, BP has been Transocean’s largest single customer, accounting for 12 percent of its $11.5 billion in operating revenue in 2009, public filings show.

Industry analysts said that strong ties between the companies reflected the fact that both had staked their financial futures on pushing oil exploration as far off shore as possible. Transocean, which drills in some 30 countries and employs more than 18,000 people, owns nearly half of the 50 or so deepwater platforms in the world.

“These people are capable and considered the gold standard of deepwater drilling,” said Peter Vig, managing director at RoundRock Capital Management, an energy hedge fund in Dallas.

Transocean’s evolution into the world’s biggest deep-sea driller follows a decade-long acquisition and merger spree.

It began in 1996 when a Texas-based company called Sonat OffshoreDrilling acquired Transocean ASA, then Norway’s largest offshore driller. Three years later, the company, now known as Transocean, shifted its headquarters for tax purposes to the Cayman Islands from Houston, though a vast majority of its executives still work in Houston. In subsequent years, it acquired or merged with other drillers including R&B Falcon, the drilling unit of Schlumberger and GlobalSantaFe. Then, in 2008, for tax purposes, it moved its headquarters again, this time to Switzerland from the Cayman Islands.

The tax investigation in Norway involves how Transocean represented the sale of 12 drilling rigs owned by its Norwegian subsidiary to another company unit, said a spokeswoman for an agency known as Okokrim, which investigates economic and environmental crimes.

The case “raises several important questions regarding the taxation of multinational corporations,” said the spokeswoman, Mie Skarpaas, who declined to discuss the investigation further.

A Norwegian newspaper, Dagens Naeringsliv, reported several years ago that a Transocean rig, while returning from a repair yard in Norway to a drilling site in the Norwegian sector of the North Sea, diverted for several hours into British waters. During that time, Transocean transferred ownership of the rig between subsidiaries and later argued that it did not have to pay Norwegian taxes because profits on the transaction had been earned outside the country. The company subsequently settled the case involving that rig.

In 2008, Norway’s highest court ruled that Okokrim and tax authorities could share documents and computer files seized during raids of Transocean and Ernst & Young which was the company’s tax adviser. That ruling also said that at least three people, including two Ernst & Young employees, were under investigation in connection with the episode.

In its statement, Transocean said that its “tax returns are materially correct as filed” and that it “will vigorously defend any claims to the contrary.” A spokesman for Ernst & Young, declined to comment.

In Myanmar, formerly Burma, a Transocean rig was under contract to a Chinese government-controlled oil company, Cnooc, as recently as this spring. Another apparent stakeholder in the drilling site, according to Cnooc, was a Singapore business. That business has been linked to two men identified by the United States Treasury Department in 2008 as major operatives and money launderers for the Myanmar government. At the time, American authorities described both men as longtime heroin traffickers.

Transocean said in a statement that its contract was with Cnooc and did not mention either man. Transocean also said it had not violated the trade sanctions against Myanmar. “No Transocean affiliate that is subject to the U.S. ban has ever done business in Myanmar,” the company said.

In the United States, the recent ruling by a federal bankruptcy court judge involved one of Transocean’s merger partners.

Judge Kevin Gross of the United States Bankruptcy Court for the District of Delaware found in May that the partner, GlobalSantaFe, had entered into a misleading bankruptcy scheme that included the use of shell companies to avoid potential liabilities in an oil pollution case. Judge Gross found the actions so egregious that he ordered GlobalSantaFe and related units to pay $2 million in sanctions to another company involved in the case.

In a statement, Transocean said the issues involving GlobalSantaFe had occurred before their 2007 merger.

Judge Gross did not mention Transocean by name. But in his ruling, he said that GlobalSantaFe and its units were still involved in a “gamesmanship with the judicial system” to thwart potential claims.

Asked about Judge Gross’s ruling, Transocean said, “We are confident we’ll prevail in the remaining legal issues that have yet to be decided.”