The Northern authorities put £1.6 million of taxpayers' money into the doomed Seagate computer plant in Limavady.
The figure for Invest NI support was disclosed by Enterprise Minister Nigel Dodds during tough questioning at an Assembly committee today.
A total 927 workers are to be paid off by next July after their manufacturing jobs were shifted to Asia.
Mr Dodds said the establishment of the Co Derry facility around a decade ago was broadly welcomed at the time.
"It is unfortunate that we have had a situation where Seagate is going to close and we know the reasons for that.... the labour costs.
"What we are determined is that the claw-back provisions that were there to ensure that the Northern Ireland taxpayer gets back money will be enforced vigorously."
Mr Dodds said the US giants had been worth over £400 million to the local economy in terms of salaries, contracts with local businesses and purchase of goods and services.
He added that positions at the company's other plant in Derry were not under threat because they were much more specialised and wage costs were a much smaller proportion of the overall budget.
He was addressing Stormont's Enterprise, Trade and Investment committee meeting as the fallout from last week's announcement continues.