(Bloomberg) -- Former traders for Barclays Plc and Deutsche Bank AG were sentenced to a combined 13 years in prison by a London judge for conspiring to rig interest-rate benchmarks.

Christian Bittar, a 46-year-old Deutsche Bank employee, was sentenced to five years and four months, while the man described by prosecutors as his fellow mastermind in manipulating the market, Barclay’s Philippe Moryoussef, received 8 years. The 50-year-old Moryoussef was sentenced in absentia after staying in France to avoid the trial.

While Bittar and Moryoussef were friends who vacationed together and made millions coordinating derivative trades, their paths diverged in the weeks before the trial started in early April. Bittar pleaded guilty to the fraud charge, while Moryoussef left London, and has since indicated he will try to avoid the U.K. judicial system.

“Derivatives trading is often said to be a form of betting,” Judge Michael Gledhill said when sentencing Bittar. “You took the analogy further by loading the dice.”

On Thursday, Bittar agreed to pay 3.3 million pounds ($4.3 million) in costs and penalties. The judge considered giving him 9 years in prison but reduced it because of his guilty plea.

The Euribor trial brings the U.K. Serious Fraud Office’s seven-year investigation into interest rate rigging towards its end. Deutsche Bank and Barclays are among financial institutions that paid more than $9 billion in fines in the U.K. and U.S. for the misconduct. SFO prosecutors won convictions for seven of the 19 individuals charged with rate-rigging offenses. The jury that found Moryoussef guilty was unable to reach a verdict on three of his former colleagues.

"Both the banks and some of their employees fell far short” of standards, Gledhill said. “Senior managers should’ve known what was going on and should’ve stopped it.”

U.K. prosecutors will seek a new trial in January for Colin Bermingham, Carlo Palombo, and Sisse Bohart in the case after the jury failed to reach a verdict on the three former Barclays traders. The panel found Deutsche Bank AG executive Achim Kraemer not guilty.

The sentences for Bittar and Moryoussef are the latest in a wave of jail terms related to financial wrongdoing. Former UBS Group AG trader Tom Hayes is serving 11 years in prison for rigging Libor and in May, an ex-Deutsche Bank AG broker received a record 4 1/2-year term for insider trading. 

Bittar and Moryoussef’s crimes were committed between 2005 and 2009, when they were derivatives traders. They wanted to improve their trading position by convincing Euribor setters at their banks to enter higher or lower values, depending on what suited them.

Moryoussef knew he was wrong to ask co-workers to change their submissions, the judge said.

“The evidence against Mr. Moryoussef was overwhelming,” judge said. “Greed was clearly his principle motive.”

Euribor is the euro interbank offered rate, a benchmark made up by submissions for dozens of lenders, who measure the cost of borrowing between each other. The published value is the average of the submissions after the top and bottom 15 percent have been eliminated.

The judge criticized the way Euribor was organized. The lack of clear instructions on how to set the rate was “at best foolhardy and at worst, negligent,” he said.

Prosecutors said Bittar was the best-paid trader they’d ever come across. He had developed such a powerful reputation that he was able to craft a deal to take home a slice of his earnings for the bank. In 2008 alone, his bonus was close to 90 million pounds ($118 million).

(An earlier version of this story was corrected to fix the former employees of the traders.)

(Adds comment from judge in 11th paragraph.)

To contact the reporter on this story: Franz Wild in London at fwild@bloomberg.net

To contact the editors responsible for this story: Anthony Aarons at aaarons@bloomberg.net, Christopher Elser

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