By Alexander Hübner FRANKFURT (Reuters) – German venture capital firm Rocket Internet and Zalando, Europe’s biggest specialist online fashion retailer, are both on the brink of announcing plans to list on the Frankfurt stock exchange, several sources with knowledge of the matter said. Both companies want to announce plans for initial public offerings (IPO) in the first half of September, meaning that the two biggest Internet listings in Germany for more than a decade could take place concurrently, the banking sources told Reuters. “So everyone is striving to tap the market as soon as possible.” Zalando, which is holding a media presentation on its business next Thursday, and Rocket Internet are likely to list stakes of around 15 percent each by selling new shares, separate sources have previously said. One banker estimated Zalando was seeking to raise around 900 million euros ($1.2 billion) and Rocket Internet about 800 million euros.