Shadow stock is a stock of an already-listed company which has the same or similar industry as a new-listed company. Since the stock price of new-listed companies mostly boosts up after being listed in a stock market, shadow stocks may also boost up to cope with the trend. However, as the increase in shadow stock price is irrelevant to the performance of the companies themselves, the stock price may drop again after such increasing power fades.
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Shadow stock Wikipedia(Text) CC BY-SA