New Delhi, May 2 -- GameStop is quietly building a stake in eBay ahead of a potential offer that could reshape online retail, as CEO Ryan Cohen pursues an audacious plan to transform the video game retailer into a $100 billion business.

GameStop is preparing to make an offer for eBay as early as this month, according to people familiar with the matter, in what would rank among the most ambitious corporate takeover attempts in recent retail history.

The video game retailer, led by chief executive Ryan Cohen, has been quietly building a stake in eBay's shares in the lead-up to a potential offer, the people said. eBay shares surged more than 15% in after-hours trading on Friday following the Wall Street Journal's initial report on the plan...