Gerald Sparrow sees blue skies ahead for stocks this year. : Gerald Sparrow, who manages the Sparrow Capital Management Fundamental Growth portfolio for Interactive Brokers Asset Management, is upbeat on the outlook for stocks in 2019. In an interview with Business Insider, which surveyed the thinking of eight money pros, Sparrow said that he’s wary of companies relying on acquisition-fueled growth. “If a company doubles its size, but it’s because they combined with another business, that would be a red flag for us,” Sparrow told (subscription required) Business Insider. “We prefer unit volume,” he added.