Carl Frampton allegedly saved hundreds of thousands of dollars by under declaring purses the High Court heard on Tuesday.
Counsel for Barry McGuigan continued to cross examine Frampton in day six of court proceedings in Belfast.
Frampton,it was alleged declared a purse of $500,000 for his July 2016 world title fight with Leo Santa Cruz when the purse was in treble that.
Without mentioning figures Frampton intimated Manager McGuigan had suggested under declaring the purse for tax purposes earlier in proceedings.
However, in court on Tuesday Counsel for the former world champion argued otherwise. It was suggested Frampton instigated the conversation with regard to declaring the lower figure.
Frampton insisted the decision had been a joint one and again claimed it was made on advice made from then manager McGuigan.
“You were the one who wanted it brought down as much as possible because you were the beneficiary of it.
“That actually saved you $300,000 (€253,000).
“When you sign the document for that purse, you knew that signing a document saying your purse was $500,000 ($422,000) was a lie.”
Mr Frampton replied: “I knew that, but my team also knew that.”
At that point Mr Justice Huddleston said wanted to “get to the bottom of this”.
“I am going to ask a subsequent question around the payment of UK tax which obviously will raise its head,” he added.
“Whether it’s for Mr Frampton or for his advisers, that is on my long list of questions coming up.”
Following the judicial intervention McGuigan’s lawyer continued suggesting that the Frampton had realised his declared earnings were untrue.
“You knew that someone was going to ask you for less money as a result of that,” he said.
Mr Frampton claimed it only related to America, and that he paid his taxes in the UK
But the barrister told him: “You know that was dishonest, and in fact if that was in this country it would be a criminal offence.”
“In this country, of you falsely account about something, dishonesty, that is a criminal offence. It’s called false accounting. You did that.”
The boxer responded: “Not in this country, no.”
It was claimed that he made a further tax saving by declarations made on the rematch with Santa Cruz in Las Vegas the following February.
Counsel for McGuigan queried Frampton’s claims it was agreed he was due 30% of Cyclone Promotions profits.
Liam McCollum stressed: “There’s emails and texts all over the papers, and there’s not one reference to request by you for any payment in respect of any 30pc profit of any shows, isn’t that right?”
The boxer said the alleged promises were “orally made”.
Later in proceedings Frampton was challenged in court over links between his management company and criminality.
Mr McGuigan’s barrister put it to Mr Frampton that his current management company, MTK Global, is a front for a criminal organisation.
“I’m not aware of that,” Mr Frampton responded.
Frampton is suing for alleged loss of earning up to the value of £6m.
A counter lawsuit has been filed at the High Court in London against Mr Frampton for alleged breach of contact when he split from the company in 2017.
The two men, both legends in the sport, deny the respective allegations against them.
The case continues.