  We propose a methodological framework to study the dynamics of inter-regional
investment flow in Europe from a Complex Networks perspective, an approach with
recent proven success in many fields including economics. In this work we study
the network of investment stocks in Europe at two different levels: first, we
compute the inward-outward investment stocks at the level of firms, based on
ownership shares and number of employees; then we estimate the inward-outward
investment stock at the level of regions in Europe, by aggregating the
ownership network of firms, based on their headquarter location. Despite the
intuitive value of this approach for EU policy making in economic development,
to our knowledge there are no similar works in the literature yet. In this
paper we focus on statistical distributions and scaling laws of activity,
investment stock and connectivity degree both at the level of firms and at the
level of regions. In particular we find that investment stock of firms is power
law distributed with an exponent very close to the one found for firm activity.
On the other hand investment stock and activity of regions turn out to be
log-normal distributed. At both levels we find scaling laws relating investment
to activity and connectivity. In particular, we find that investment stock
scales with connectivity in a similar way as has been previously found for
stock market data, calling for further investigations on a possible general
scaling law holding true in economical networks.
