By Josep LAGO / AFP European regulators have launched an investigation into Microsoft’s acquisition of Activision Blizzard, the biggest buyout in video game history. European regulators have launched an investigation into Microsoft’s acquisition of Activision Blizzard, the biggest buyout in video game history. The deal announced in January capped a series of blockbuster takeovers that has left four major players still standing in an industry estimated to be worth $300 billion. \- Tencent: Global number one – China-based Tencent is the biggest player in the market in terms of revenue. It is a h…