Chris Ashton, Rohan Ramchandani and Richard Usher, who worked at Barclays Plc, Citigroup Inc and JPMorgan Chase & Co, respectively, entered their pleas through their lawyers before U.S. District Judge Richard Berman in Manhattan.
The defendants were charged in January, and agreed last month to appear in Manhattan rather than fight extradition.
According to prosecutors, the defendants schemed with other traders to share sensitive client order information through phone calls and an electronic chat room known as the "Cartel" to suppress competition.
Ashton was Barclays' global head of spot currency trading, Ramchandani was Citigroup's head of G-10 spot currency trading, and Usher was chief currency spot trader at JPMorgan.
Ramchandani and Usher were involved in the conspiracy from roughly December 2007 to January 2013, and Ashton from December 2011 to January 2013, according to the indictment.
Bail was set at $200,000 for Ashton, $1 million for Ramchandani and $650,000 for Usher.
Berman ordered the defendants to next appear in court on Nov. 9, and set a June 4, 2018 trial date.
The case followed worldwide probes that resulted in about $10 billion in fines for several large banks and the firing of dozens of traders.
Britain's Serious Fraud Office decided in March 2016 to close its own criminal probe, saying it lacked a "realistic prospect" of obtaining convictions.
In separate statements, lawyers for Ramchandani and Usher said their clients waived extradition to contest the charges and clear their names. A lawyer for Ashton declined to comment.
The defendants plan to jointly seek dismissal of the case.
Three other traders have also been implicated in the U.S. probe.
In January, former Barclays trader Jason Katz pleaded guilty to conspiring to fix currency prices, becoming the first person to admit wrongdoing. His sentencing is scheduled for Jan. 5, 2018.
U.S. prosecutors also charged two one-time HSBC Holdings Plc foreign exchange executives, Mark Johnson and Stuart Scott, last July with fraudulently trading ahead of a client's $3.5 billion currency trade.
Johnson pleaded not guilty to wire fraud and conspiracy charges, and faces a Sept. 18 trial. Scott was arrested by British authorities last month and has denied wrongdoing. He has a July 31 hearing in Britain.
The case is U.S. v. Usher et al, U.S. District Court, Southern District of New York, No. 17-cr-00019.
(Editing by Jeffrey Benkoe and Jonathan Oatis)
By Jonathan Stempel