Mark O'Sullivan

Partner, Research & Development Incentives, BDO Dublin

Financial Services | International Services

Research, Development, and Innovation Incentives

Executive summary


Mark is head of BDO’s dedicated Research and Development (“R&D”) Incentives practice, the largest engineer led practice of its kind in the country. Mark has significant experience working with companies in all areas of R&D incentives, having specialised in this area in both KPMG and BDO since 2011. Mark has been involved in the successful qualification of well over €600 Million worth of R&D expenditure through these incentives since joining BDO.

During this time Mark has also been involved in compiling hundreds of R&D tax credit claims and qualifying thousands of projects. This includes compiling and defending a number of the largest R&D tax credit claims ever made in the country.


As R&D Incentives Partner, Mark specialises in securing R&D funding for companies through government grants and tax incentives, including RD&I grants, R&D tax credits, and the Knowledge Development Box (“KDB”) regime. These incentives can offer savings of over 50% of the cost of your R&D, as well as a reduced effective tax rate as low as 6.25% on resultant profits.

Mark has extensive Revenue audit experience and has successfully qualified and defended numerous multimillion euro R&D tax credit claims. This success is largely based on the knowledge set and methodology utilised, coupled with the due diligence placed on the review process undertaken with clients prior to inclusion of projects in a claim.

Mark is a member of Engineers Ireland and has professional qualifications in Medical Physics, Mechanical Engineering, Manufacturing & Design Engineering, Computer Science, and Tax.

Mark also holds a Certificate in Sustainability Strategy, Risk and Reporting from Chartered Accountants Ireland.