Growth Thickens Big‑Firm Tail

Across countries and over time, the right tail of the firm‑size distribution systematically gets heavier as economies develop; a formal idea‑search growth model explains this transition, predicts convergence toward Zipf’s law, and implies that large firms create positive externalities from concentrated idea search. The model also generates the policy conclusion that measures favoring large firms may sometimes improve welfare because of those search spillovers. — This reframes concentration debates by linking macroeconomic growth to firm‑size evolution and providing a welfare argument for industrial policies that tolerate or support large firms.