Giorgia Maffini is a Research Fellow at the Oxford University Centre for Business Taxation at Saïd Business School, University of Oxford. Her areas of expertise include public finance, taxation and business taxation.

Maffini has been a Research Fellow at the Oxford University Centre for Business Taxation since 2006.  Since May 2010 Dr. Maffini has also been a visiting Lecturer at the Department of Policy Analysis and Public Management, Bocconi University, Italy, where she teaches Business Law and Public Finance. Previously she was an Economist at the Centre for Tax Policy and Administration (CTPA) of the Organization for Economic Cooperation and Development (OECD) in Paris (2004-2005); a Research Assistant at the Department of Economics of the University of Warwick (2003-2004) and at the Institute of Political Economy, Bocconi University, Italy (2001-2002).

Maffini holds a PhD in Economics from the University of Warwick;  a PhD in Public Finance from the University of Pavia, Italy ; a Masters in Economics from University College of London and an undergraduate degree in Economics and Social Sciences from Bocconi University, Milan, Italy (summa cum laude).

Maffini conducts research on public finance, business taxation and tax incidence. She works both independently and collaboratively with colleagues at the University of Oxford, at Bocconi University, Milan, and around the world.

Maffini’s current research on the territoriality and competitiveness of multinational companies uses firm-level accounting data to compare the tax burden of companies headquartered in countries with worldwide jurisdictions (such as the US or UK) with that of companies headquartered in territorial countries.  This work employs a novel methodology developed by Maffini to measure the tax burden of corporate entities by marginal effective tax rate (METR) and marginal effective tax base (METB).  The METR measures the increase in the tax bill, given a marginal increase in accounting profit. The METB measures the increase in the tax base, given a marginal increase in accounting profit. Results suggest that a higher tax burden for entities headquartered in worldwide jurisdictions is explained by higher corporate statutory tax rates, rather than by the difference in the taxation of foreign profits.  Maffini’s research also explores the potential vulnerability of territorial jurisdictions to tax avoidance by multinational companies, suggesting that offshore low-tax operations reduce the marginal effective tax rate and the marginal effective tax base of multinationals more in territorial systems than in worldwide systems.  A recent paper sheds some light on the recent decision of the UK to move to a territorial system and on the current debate on whether the US should move to a territorial system of taxation of foreign profits.

Another of Maffini’s current research projects with high policy relevance explores the factors determining corporate tax payments in developing countries.   This research suggests that between 1999-2008, large firms across 65 developing countries faced higher tax rates than smaller firms, and importantly, that the affiliation to a multinational group does not significantly affect tax payments.   Significantly, Maffini’s research also suggests that public sector corruption in the developing countries studied is correlated with a lower tax bill at the corporate level.

Business taxation, tax incidence and avoidance
Territoriality, Worldwide Principle, and Competitiveness of Multinationals:  Firm-level Analysis of Tax Burdens

Using consolidated firm-level accounting data for about 3,400 companies in 15 OECD countries covering 2003-2007, Maffini compares the tax burden of companies headquartered in worldwide countries with that of companies headquartered in territorial countries. The tax burden is measured by a marginal effective tax rate (METR) and, employing a new methodology, by a marginal effective tax base (METB) which controls for statutory corporate tax rates. A higher METR for entities headquartered in worldwide jurisdictions is explained by higher corporate statutory tax rates rather than by the difference in the taxation of foreign profits. The METB of companies headquartered in worldwide countries is not statistically different from that of companies headquartered in territorial countries. Using corporate presence in tax havens, the paper also investigates the vulnerability of territorial jurisdictions to tax avoidance. The results show that offshore low-tax operations reduce the METR and the METB of multinationals more in territorial systems than in worldwide systems.

Taxation in Developing Countries
This research explores the factors determining corporate tax payments in developing countries. Using rich accounting and ownership data on approximately 183,000 firms in 65 developing countries for 1999-2008, we find that large firms face higher marginal and average effective tax rates than smaller firms. Being affiliated to a multinational group in turn does not play a significant role in determining effective tax payments. The results also suggest that public sector corruption exerts a negative impact on observed effective tax rates.