The relevant “time” for financial markets is present: market prices incorporate the expected consequences of financial operations upon their annoucement, which gives an indication on their consequences for the firms implied, their competitors, and even consumers.The examination of stock price reactions in the case of mergers and acquisitions reveals that wealth effects of horizontal arrangements are larger than others, although it is hard to know whether it is due to an increase in production efficiency or an increase in market power. Moreover, it shows that the financial market seems to be able to predict the final decision of the competition authorities from the very first annoucement of the merger project.
CHARLETY-LEPERS, P. (2003). Le temps et la valeur des entreprises : l’exemple des offres publiques. Revue de la Concurrence et de la Consommation, pp. 35-37.