Jay Merchant was convicted unanimously at the end of a 10-week trial at Southwark Crown Court last week but reporting restrictions on the case were lifted only today.
The 45-year-old was found guilty alongside 35-year-old Jonathan Mathew and 38-year-old Alex Pabon and they will all be sentenced on Thursday.
Merchant shook his head in disbelief while his elderly father looked stunned as the verdicts were read out last Wednesday, the 'Guardian' reports.
Libor rate stands for London inter-bank lending rate and is used by banks to set prices of financial products.
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The crucial rate forms the base for trillions of pounds worth of loans and financial contracts for households and companies across the world.
Between 2005 and 2007, 16 banks, including Barclays, submitted daily estimates of borrowing rates to the British Banker' Association, which used them to calculate Libor.
The trial jury heard the ability to organise even minor movements in the rate had the potential to generate large profits for a trader.
The prosecution had claimed that Merchant was among four traders who asked Libor rate submitters, Mathew and Peter Johnson, to put in rates that suited their trading at the daily setting of Libor.
They had argued that they should not be found guilty because they did not know they were behaving dishonestly and so did not meet the legal definition of fraud.
The jury was unable to reach a verdict in relation to two other defendants, Ryan Reich and Stelios Contogoulas.
The UK's Serious Fraud Office (SFO) now has to decide whether to call a retrial for them.
This was the third case to be brought by the SFO into Libor manipulation.
Libor manipulation instances emerged nearly four years ago and Barclays itself had to pay 290 million pounds in fines in relation to the scandal.