The London Stock Exchange and Germany's counterpart, Deutsche Börse, are in talks to merge, creating a superpower that could rival its US competition.

At $28.3B, the all-share merger would be the largest stock exchange in Europe by shares traded, and a deal that would leave three giant global exchange companies: US market leaders CME Group and Intercontinental Exchange, and, of course, the proposed LSE-Deutsche Börse.

Talks are being pushed by futures and options, instruments with higher margins than stocks and tougher to replicate by rivals, and markets where euro exchanges have been facing fierce competition, the Wall Street Journal reports.

Before the European superpower can start annexing market share, the exchanges still would need to pass antitrust ruling by the European Commission, as well as local regulators—something that put a stop to another proposed mega-merger back in 2012. [WSJ]