The Serious Fraud Office has closed its long-running investigation into the rigging of the benchmark Libor rate.
The probe, which was announced in July 2012, has seen 13 people charged with conspiracy to defraud and five convictions.
Libor is a benchmark rate used to set millions of pounds worth of financial deals, including car loans and mortgages.
It is also used in complex overseas financial transactions.
A SFO spokesman said: “Following a thorough investigation and a detailed review of the available evidence, there will be no further charges brought in this case.
“This decision was taken in line with the test in the Code for Crown Prosecutors.”
Former Barclays trader Peter Johnson pleaded guilty to manipulating the US Dollar Libor in October 2014 to become the first criminal conviction for a Libor offence in the UK, according to the SFO – which investigates and prosecutes serious or complex fraud, bribery and corruption.
Ex-Barclays employees Jonathan Matthew, Jay Merchant and Alex Pabon were convicted by a jury at London’s Southwark Crown Court of the same charges in July 2016.
Former Citigroup and UBS trader Tom Hayes was convicted in August 2015 of eight counts of conspiracy to defraud.
The SFO said that between January 2016 and April 2017, six people were acquitted by jury of manipulating the Yen Libor and two were found not guilty of manipulating US Dollar Libor.
The SFO said that “all strands” of the Libor rigging investigation are now closed.