By Nate Raymond

(Reuters) - A former Rabobank trader from Australia will plead guilty on Thursday to U.S. charges that he conspired in a huge scandal to manipulate Libor, the leading benchmark for pricing financial transactions, his lawyer said.

The expected plea by Paul Thompson, former head of money market and derivatives trading in Northeast Asia for the Dutch bank, was disclosed by his attorney, Harry Sandick, at a hearing on Wednesday in Manhattan federal court.

Thompson, 50, who faces charges of conspiracy and wire fraud, was extradited from Australia and released on a $500,000 bond after the hearing.

Libor, or the London interbank offered rate, underpins trillions of dollars of financial products globally from mortgages to credit cards. The rate is based on what banks say they believe they would pay if they borrowed from other banks.

U.S. and European authorities have been probing whether banks attempted to manipulate the rate to benefit their own trading positions. Investigations have resulted in roughly $9 billion in sanctions worldwide against financial institutions.

The U.S. Justice Department has charged 16 people, including seven former traders at Rabobank, which in 2013 reached a $1 billion deal to resolve related U.S. and European probes.

Thompson was charged in 2014 and arrested in October in Australia at the request of U.S. authorities, while two other ex-Rabobank traders, Anthony Allen and Anthony Conti, were undergoing trial in New York.

Both were convicted in November for conspiring with Thompson from 2006 to 2011 to manipulate the U.S. dollar and yen Libor rates to benefit the bank's trading positions.

In March, Allen was sentenced to two years in prison, while Conti was sentenced to one year in prison. Both are appealing.

Three other Rabobank traders have pleaded guilty.

Thompson's extradition came as Britain's Serious Fraud Office said it would seek the retrial of two ex-Barclays <BARC.L> traders, Stylianos Contogoulas and Ryan Reich, after jurors were unable to reach a verdict in their Libor-related case.

Three other Barclays traders, Jonathan Mathew, Jay Merchant and Alex Pabon, were found guilty. A fourth, Peter Johnson, pleaded guilty to conspiracy to defraud. The men will be sentenced on Thursday.

In total, 12 people have faced trial in the United Kingdom in relation to the Libor probes. Jurors there have convicted four individuals and acquitted six others.

The case is U.S. v. Thompson, U.S. District Court, Southern District of New York, No. 14-cr-272.