American prosecutors have dropped charges against a New Zealand resident accused of conspiring to manipulate benchmark interest rates.

The move comes near six months after the Wellington man was acquitted in the United Kingdom of similar allegations.

Darrell Read, in 2013, was charged by US prosecutors with two counts of wire fraud and another of attempting to commit wire fraud.

Read and two co-defendants were accused of conspiring to manipulate Libor to benefit a client, UBS' Tom Hayes, who is now serving an 11-year jail sentence after becoming the first person to be convicted over the rigging of the rate.


See a timeline showing key points of the Libor case:

The Libor (London interbank offered rate) set the scene for banks, mortgage lenders and credit card companies and financial instruments, worth hundreds of trillions of US dollars, are tied to it the world over.

But some three years after charging Read, US prosecutors have now dropped the case.

"The United States moves to dismiss the complaint because of the final adjudication of the case against these defendants for the same underlying conduct in the United Kingdom," prosecutors said in a filing with a court in the Southern District of New York last month.

The application was granted.

Despite the fact that Read and his co-accused were charged in the US first, a case brought by the UK's Serious Fraud Office making similar allegations went to trial before it.

Those proceedings stretched on for more than three months but a jury in London's Southwark Crown Court took only two days to find Read and his five co-accused not guilty on all the charges they faced.