He carried out 16 paint and glue attacks across Dublin in three weeks after the bank increased his monthly mortgage payments on a second property six fold.
Mahon told the Evening Herald newspaper: “I felt really stressed, but I apologize for what I did.
“I had an interest only mortgage on a second property and went into meltdown when the monthly payments went up by 600pc. The bank refused to discuss alternatives.”
Reacting to the bank’s unwillingness to discuss the issue, Mahon carried out the attacks to disable the ATMs.
He told the paper that he ‘deeply regretted’ disabling the ATMs and was relieved that the bank agreed to accept $6,500 compensation for the damage.
His lawyer Jenny McGeever told Dublin District Court that the bank had offered to accept the compensation on condition that Mahon undertakes not to damage any of its property again.
She said: “I am hoping, in the view of the very generous and gracious approach the bank has adopted, that the court can finalize matters.”
Judge Victor Blake adjourned sentencing for two weeks and Mahon was remanded on continuing bail until July 26.
Mahon had bought a rental property in Limerick in 1999 for €80,000, and later got an interest-only mortgage through Ulster Bank.
In October 2011, he was ‘suddenly’ contacted and told the repayments were reverting to capital and interest.
McGeever said: “He called the bank to attempt to draw up a schedule of repayments, and did everything he humanly could to deal with the situation in an adult and responsible fashion but was met with a blank wall.
“He also suffered ill health and went into meltdown before carrying out the damage. He did not think the damage to the machines would be as severe as it was, and thought they could be cleaned and would be okay again.
“This is not a case of wanton damage. This pressure overcame him and he acted very uncharacteristically.”
After his court appearance, Mahon told the Herald: “I would like to warn people that switching to an interest-only agreement can result in very high repayments once the interest-only term ends.
“I realize I broke the law and caused the gardai (police) a lot of paperwork, for which I apologize. I did not think the damage was going to be as serious as it was. I deeply regret doing it.
“I had felt the bank was being very unreasonable by not responding to several of my proposals to make a deal with them on repayments, and I got frustrated by the lack of replies.
“I’ve suffered depression in the past and all the stress of what happened contributed to making me ill again and I spent five weeks in St John of God’s Hospital after Christmas. I’m still on medication.
“The bank phoned me afterwards and offered to put me on €150 interest-only payments. But I told them I had managed to rent out the Limerick flat for €400 a month and we have agreed on €300 repayments on the mortgage.”
Mahon also said he feels angry about the State’s bailout of the banks.