Opendoor is the breakout meme stock of the season. Hedge fund manager Eric Jackson has activated an army of retail traders who are piling into the stock. Three market pros tell us why they're skeptical of the rally. The rise of Opendoor Technologies was the biggest story in retail-trader circles over the summer. Since the start of July when hedge fund founder Eric Jackson posted his bullish outlook, shares of the online real estate company have surged more than 1,600%, rising from less than $1 per ...