The office of Tehran’s public prosecutor announced that Mahafari Amir-Khosravi, one of the four co-conspirators given the death sentence in 2012 for their roles in embezzling the equivalent of $2.6 billion, was hanged inside Tehran’s Evin prison.
Among those accused in the case were executives at seven of Iran’s largest banks, and the managing director of the biggest one, Melli Bank, is still at large having fled the country to Canada soon after the details of the case were announced in September 2011.
He faces charges over the case in Iran and remains on the Islamic Republic's wanted list.
Amir-Khosravi was convicted of forging letters of credit, proceeds of which were later used to set up a private bank.
Plans for his execution had not been made public and his death caught many by surprise.
When the scandal in which a group of powerful businessmen conspired with bank managers to rob public coffers became public, it set off a month-long national controversy that many felt went unpunished, believing that the case would result in little more than slaps on the wrists of those involved.
At the time, much of the blame was directed at the chief of staff and political confidant of the former administration, Esfandiar Rahim Mashaei.
The fraud involved using forged documents to get credit at one of Iran's top financial institutions, Bank Saderat, to purchase assets including state-owned companies like major steel producer Khuzestan Steel Co.
Khosravi's business empire included more than 35 companies from mineral water production to a football club and meat imports from Brazil. According to Iranian media reports, the bank fraud began in 2007.
A total of 39 defendants were convicted in the case. Four received death sentences, two got life sentences and the rest received sentences of up to 25 years in prison.