The number of people at the Economic and Social Research Institute (ESRI) earning more than €100,000 increased from 12 to 16 last year.
New accounts for the ESRI show that two of the 16 earned above €150,000. Salaries last year increased to €8.33m from €6.8m.
The ESRI recorded a surplus of €147,240 - a 24pc drop on a previous surplus of €194,183 in 2017.
Overall income dipped marginally, to €11.3m from €11.5m. The accounts also reveal that the spend on staff international travel last year fell to €91,190 from €132,052.
In a statement attached to the accounts concerning procurement, chairman of the ESRI, Padraig McManus, said certain survey services were not tendered for in the period under review.
Mr McManus stated: "€95,830 was paid to Amarach in respect of survey services for a specific project.
"As the funding for this project was uncertain due to the withdrawal of the main funder, it was not feasible to operate a tender process as planned ... The project came to a completion in April 2019."
The surplus last year takes account of non-cash depreciation costs of €416,485. The ESRI's research income is made up of €3.3m from research programmes; €2.6m from the Growing Up in Ireland Survey; €1.3m in research grants and €969,625 in commissioned research.
The ESRI received a grant of €2.77m from the Department of Public Expenditure.