Retired British businessman Christopher Tappin is expected to reach a deal with prosecutors next week.
Christopher Tappin, 65, was extradited to the US in February on charges of conspiring to sell batteries for Iranian missiles and faced up to 35 years in jail if convicted.
But US prosecutors said he will now appear in court on Thursday to re-enter his plea, just four days before his trial in Texas is due to start.
Tappin, from Orpington, Kent, is currently on bail in the US.
The former president of the Kent Golf Union has always denied attempting to sell batteries for surface-to-air missiles which were to be shipped from the US to Tehran via the Netherlands.
No details of any plea deal with Tappin have been released, but other Britons who have been extradited said they had no chance of being cleared once sent to the US as the plea bargaining system empowers prosecutors as "judge, jury and executioner".
David Bermingham, who was one of three bankers jailed for 37 months over an Enron-related fraud in a deal with US prosecutors in 2008, said in March that no sane defendant would risk dozens of years in jail when a plea bargain could enable them to be home within months.
Plea bargaining is common in the US, with defendants often able to secure a more lenient sentence if they admit an offence and co-operate with prosecutors, rather than contest the charges in a trial.
But the system, and the pressure it places on defendants, leaves those extradited to the US from the UK with little choice but to accept a deal if they want to return to their families at home, Bermingham, of Goring, south Oxfordshire, claimed in March.
"A prosecutor can now effectively be judge, jury and executioner," he said.
"He can say, 'I'm going to charge you with 98 different counts, each carrying a five or 10 year maximum sentence, and potentially you could be sentenced to literally the rest of your life in prison'.
"And there's no parole. There's no two ways about it.
"A prosecutor can threaten a defendant with the rest of his life in prison. However if you are willing to plead guilty, 30 years becomes five years.
"If you are then cooperating and willing to give evidence against others, five years becomes two."
US prosecutors often quote maximum sentences, rather than the most likely jail term, for each offence, in part to act as a deterrent to others.
Tappin will enter a plea at the court in El Paso, Texas, at 4.30pm (11.30am local time) on Thursday, US court documents showed.