New York (CNN Business) Less than two months after Apple refreshed its smartphone lineup, investors are once again panicking about whether enough people are buying iPhones.

Apple's ( AAPL ) stock fell 1% Tuesday after tumbling 5% on Monday, shaving off tens of billions of dollars in market value. The stock fell after iPhone parts suppliers Japan Display and Lumentum Holdings cut their sales outlooks . On Tuesday, another Apple supplier, Qorvo, followed suit in cutting its forecast, citing "recent demand changes for flagship smartphones."

Although the suppliers did not mention Apple specifically, the announcements were quickly interpreted by Apple analysts and investors as a possible warning sign of weaker than expected iPhone demand.

Citing the Lumentum cuts, Goldman Sachs analysts expressed "concern" in an investor note Tuesday that "demand for new iPhone models is deteriorating." Yet in the very next sentence, the analysts said Apple "could easily right itself given the bulk of demand comes in late December."

Such is the uncertainty that comes with trying to read the tea leaves for the world's most valuable company. Even dire forecasts from multiple suppliers may not be enough to give a complete and accurate picture of Apple's sprawling global business.

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