Star: Stars represent business units having large market share in a fast growing industry. They may generate cash but because of fast growing market, stars require huge investments to maintain their lead. The portfolio of a diversified company always should have stars that will become the next cash cows and ensure future cash generation.
Question Mark: Question marks are growing rapidly and thus consume large amounts of cash, but because they have low market shares they do not generate much cash. The result is large net cash consumption. A question mark has the potential to gain market share thus becoming a star and gradually a cash cow when the market growth gets stable. It will degenerate into a dog when the market growth declines. Question marks must be analyzed