Square Enix Holdings has shed nearly $2 billion of its value since Final Fantasy XVI, the latest installment of its global hit series, came out to mixed reviews. Now investors wonder whether one of the games industry’s most remarkable runs is coming to an end.

The Tokyo-based firm has long relied on its feted franchise to supercharge growth — a formula that lifted its value fivefold in the decade leading to the launch of the latest Final Fantasy in June. But the game’s sales underwhelmed, and things got worse in August after the company reported a sharp profit decline. Shares plummeted by double digits, a dozen analysts tracking the stock cut their price target and long-term investor Sumitomo Mitsui Trust Asset Management slashed its holdings in the game company.

One of the most recognized names among console and mobile gamers, Square Enix is on a streak of misfires in attempts to build another hit series to buttress sales, and it’s fallen behind rivals like Capcom and Activision Blizzard in terms of market value. The company’s fall from grace offers hard lessons for the industry about the importance of quality control and product planning, said fans, analysts and developers who have done business at or with the studio.