Invest NI has offered global banking group Citi £37m of financial assistance over the last 10 years.
The figure was revealed as the body injected almost £6m into a total investment of £54m by the company, which will create 600 new jobs in Belfast.
From that figure, £4.5m of Invest NI money is going directly towards supporting the new human resources, compliance control, finance and risk management roles.
Changes to EU rules on State Aid at the end of June this year have restricted support which government can give to firms already operating in a region.
Including support, Citi has now invested £165m into the economy here, to create a total of 2,100 jobs, 1,500 of which are already in place.
The new jobs will have an average salary of £35,000 and will contribute £21m to the economy here, annually.
Back in 2004, Citi was one of the first to base itself in the Titanic Quarter and is soon to take out the remaining two floors of the Gateway building.
James Bardrick, Citi country officer for the United Kingdom, said that as a former mechanical engineer, he used to make products for use by shipbuilders Harland & Wolff and planemaker Shorts, now Bombardier.
He said that he was pleased to be part of the regeneration of an area formerly known as a manufacturing base into a leading tech, science and banking hub.
"Just like Canary Wharf in London, this is a former dockland area enjoying a new lease of life," he said.
"We have been delighted with the performance of the Belfast office and with the staff.
"Our close working relationship with both the government and the universities and colleges means we are keen to grow our presence in Northern Ireland."
Invest NI chief executive Alastair Hamilton justified the investment, saying there was strong competition from Citi facilities elsewhere for the new jobs.
"There were at least three locations strongly vying for these jobs," he said. "Citi operates in 100 countries and the roles could have gone anywhere.
"During the negotiations, Citi actually increased the number of new jobs for Belfast, the original estimation of new jobs required was less than 600."
Deputy First Minister Martin McGuinness said that the investment would be repaid many times over through the contribution that the salaries will make to the economy.
"Financial companies operate in clusters and Citi's initial vision has attracted many other companies now creating jobs which are contributing millions to the Northern Ireland economy."
He added that during trade missions overseas to attract inward investment to Northern Ireland, executives of companies like Citi were "the best advocates" for the business benefits that the region offers international firms.
Paul Gosling, a personal finance columnist and commentator, said a reduction in the rate of corporation tax would mean that inward investors could rely less on grant aid from agencies like Invest NI.