* Transocean companies, advisers acquitted of all charges
* Norwegian state must pay defence's costs
OSLO, July 3 (Reuters) - Swiss-based rig operator Transocean and three advisers were acquitted of tax fraud in connection with shifting assets between subsidiary companies, a lawyer in the Norwegian case said on Thursday.
Norwegian authorities sued several Transocean subsidiaries along with their individual advisers for 1.8 billion crowns ($290.74 million) in damages.
"Everyone, both the companies and the individuals charged, were acquitted of all charges," Erling Olav Lyngtveit, the lawyer who headed the defence team, told Reuters.
The Oslo court dismissed the prosecution's demand for damages. Instead it asked the Norwegian state to pay the defendants' costs, or 41 million crowns.
Transocean said it was evaluating the decision: "(The company) will take action, as necessary, to continue to support its position that its Norwegian tax returns are materially correct as filed."
The company was accused of having underpaid taxes in 2000-2002, when it acquired three rivals worth $27 billion and moved its own headquarters to Switzerland from the Cayman Islands. It has since relocated back to Switzerland.
The prosecution claimed that the underpayments stemmed from several transactions in connection with the sale of 12 oil rigs from Transocean's Norwegian subsidiary to other company divisions.
Transocean was also accused of several instances of providing tax authorities with incomplete or misleading information.
The Norwegian police unit that investigates economic crime launched an investigation into the transactions in 2005.
The prosecution has 14 days to decide whether they want to appeal the decision by the Oslo court.
($1 = 6.1910 Norwegian Kroner) (Reporting by Gwladys Fouche; editing by Foo Yun Chee)