https://www.cnbc.com/2018/11/12/apple-analysts-have-a-long-history-of-misreading-weak-iphone-demand.html

Stop me if you've heard this one before: An Apple analyst cuts iPhone shipment estimates based on weak supplier guidance, sendingthe company's stock is tumbling.

That's the situation Apple was in Monday. Shares fell 5 percent, leading the overall market to painful declines, after iPhone supplier Lumentum cut its outlook.