Former Barclays traders Jay Merchant, 45, and Alex Pabon, 38, and former Libor submitter Jonathan Mathew, 35, all stood trial charged with conspiracy to defraud.
The prosecution said that the trio of former bankers worked together to manipulate US dollar-linked Libor between June 2005 and September 2007.
Merchant was found guilty by a unanimous verdict, while Mathew was found guilty by an 11 to 1 majority and Pabon by a 10 to 2 majority.
The jury delivered its verdicts last week but they could not be reported until today because of a court restriction. Reporting restrictions were lifted today after the jury failed to reach a verdict on two other defendants.
The jury was initially sent out to consider its verdict last Monday.
The trial, which was heard at Southwark Crown Court and started in April, is the third brought to court by the Serious Fraud Office in its ongoing investigation into Libor manipulation.
A second Libor submitter, 61-year-old Peter Johnson, had pleaded guilty. The men are expected to be sentenced on Thursday.