Recognizing how financial shocks are transmitted to national economies will enable policymakers to take appropriate fiscal and monetary policy action. Such actions will be able to prevent or reduce the intensity of shocks to critical macroeconomic variables. Observing the financial crises in countries of the European Union and Argentina, highlights the main similarities and differences they present in the context of their course in international economic conditions. This study investigates the relation among international stock indices of major importance and stock indices of less developed economies during normal periods and the Covid-19 pandemic by employing a Vector Autoregression (VAR) framework. Econometric outcomes indicate that the German DAX30 and the British FTSE100 indices are positively influential towards the Greek ATX and the Portuguese PSI20 indices. Notably, this impact is revealed to fade out as more lags are considered. Moreover, the French CAC40 index is found to exert negative effects on the Greek and Portuguese indices and its impacts also diminish as time passes. Notably, the Argentinian stock index is found to be both a transmitter of purely negative effects towards the Italian and the Spanish stock indices while impacts on the Greek and the Portuguese indices turn into positive with the evolution of time. Nevertheless, its influence on stock indices of more advanced economies (DAX30, FTSE100) is found to be weaker. This paper serves as a compass for interested investors in order to better allocate their resources during normal periods as well as during crises.