I am an assistant professor at the Department of Economics of the University of Macedonia since September 2024. I obtained my Ph.D. from the University of Padova, Italy.
I am mainly interested in applications of real-options games in industrial organization, energy economics and agricultural economics.
Contact:
Department of Economics
University of Macedonia
156 Egnatia Street, GR-546 36 Thessaloniki, Greece
+30 2310 891.688
zormpas <at> uom.edu.gr
Publications:
Journal of the Operational Research Society, 2026
The paper discusses how the threat of nationalization affects the timing and scale of foreign investments. The threat of nationalization leads to premature and undersized investments, rather than deterring them entirely.
Strategic capacity investment with common ownership - with Richard Ruble and Domenico De Giovanni
European Journal of Operational Research, 2025
The paper studies how common ownership (CO) affects the magnitude and dynamics of investments in a duopoly with exogenous or endogenous roles. In all cases CO is detrimental to consumer surplus and welfare.
Evaluating the optimal timing and capacity of investments in flexible combined heat and power generation for energy-intensive industries - with Giorgia Oggioni
Annals of Operations Research, 2023.
The paper shows that operational flexibility guarantees earlier investment in flexible cogeneration systems but has an ambiguous effect in terms of capacity.
Investment in farming under uncertainty and decoupled support: a real options approach - with Luca Di Corato
European Review of Agricultural Economics, 2022.
The paper shows that decoupled payments (i) induce earlier investment with lower productive capacity; (ii) increase the value of the investment option associated with land and (iii) reduce the volatility of farm income.
The dynamics of preemptive and follower investments with overlapping ownership - with Richard Ruble
Journal of Economic Dynamics and Control, 2021.
The paper shows that overlapping ownership arrangements delay follower entry implying longer incumbency which intensifies the race to lead.
Excess returns in Public-Private Partnerships: Do governments pay too much? - with Michele Moretto and Marco Buso
Economic Modelling, 2021.
The paper discusses the optimal design of Public Private Partnerships under moral hazard when the private party has bargaining power.
Investing in electricity production under a reliability options scheme - with Fulvio Fontini and Tiziano Vargiolu
Journal of Economic Dynamics and Control, 2021.
The paper shows that reliability options can have adverse effects on investment timing and value.
Review of Industrial Organization, 2021.
The paper shows that the optimal time for exercising a jointly held investment option depends on the bargaining power distribution between the option holders as well as the upstream market power. The latter is always prevailing.
The effect of vertical relationships on investment timing - with Rossella Agliardi
International Game Theory Review, 2021.
The paper discusses the effect of demand and investment cost uncertainty as well as upstream market power on investment timing.
International Review of Economics & Finance, 2020.
The paper discusses the effect of downstream information asymmetries on upstream suppliers.
Working Papers:
Overlapping Ownership, Sequential Moves, and Welfare - with Richard Ruble and Domenico De Giovanni
R&R (a preliminary version is available here)
We introduce overlapping ownership into a sequential-move duopoly and draw welfare implications contrasting with those of other standard oligopoly models. Internalization of rival profits softens follower output and entry decisions, prompting more aggressive leader behavior. Overlapping ownership thereby exerts a procompetitive effect on market outcomes via two mechanisms. First, in a Stackelberg equilibrium higher follower internalization increases leader output enough to raise welfare under general conditions. Second, in an entry deterrence framework, higher follower internalization shifts the leader's strategy from accommodation to deterrence which raises welfare, particularly relative to the benchmark scenario where firms maximize profits independently.
Irreversible Investment with Endogenous Scale under Kinked Subsidy Schedules - with Luca Di Corato
Under review (a preliminary version is available here)
We study an irreversible investment problem with endogenous scale under uncertainty, characterized by a concave subsidy schedule featuring a policy-induced kink. Using a real options framework, we analyze how the structure of policy support, in particular, the presence of threshold-induced kinks, reshapes optimal investment timing and scale. Motivated by the recent reform of the Common Agricultural Policy, which introduced redistributive payments linked to "first hectares", we show that nonsmooth support schemes fundamentally alter investment incentives. Smaller projects respond to higher subsidies by expanding investment scale without affecting timing, while larger projects exhibit non-monotonic responses: higher basic payments encourage expansion but delay investment, whereas stronger redistributive components induce earlier investment in smaller projects. These asymmetric responses generate a pooling effect around the policy threshold, whereby heterogeneous investors optimally converge to similar project sizes. By introducing policy-induced kinks into a real options model with endogenous scale, the analysis shows that redistributive subsidies can generate pooling and non-monotonic timing-scale responses that cannot arise under smooth or linear payoff structures. More generally, the results highlight how non-linear subsidies affect irreversible investment decisions, with implications for subsidy capitalization and the dynamic allocation of land.
Non-monotonic entry dynamics in oligopoly with common ownership - with Richard Ruble and Domenico De Giovanni
Under review (a preliminary version is available here)
We show how common ownership fundamentally transforms entry in an uncertain market from sequential preemption into a regime of coordination with contest-like dynamics. We do this by studying an industry with three firms facing a stochastically evolving demand that internalize the effect of their entry and output decisions on rivals. Equilibrium exhibits an accordion effect with respect to internalization: common ownership softens the last entry, intensifies competition at the duopoly stage, and ultimately slows down first market entry, reducing overall dynamism. But unlike in two-firm industries, a coordination equilibrium emerges at the duopoly stage if option value is high enough. The contest-like dynamics in this equilibrium accelerate first entry and raise welfare.
For regular updates of my work check my ResearchGate profile.