Apple stock hammered on lower forecasts from iPhone part suppliers Lumentum & Japan Display

Two important Apple suppliers — Japan Display and TrueDepth sensor provider Lumentum — have cut their revenue forecasts, causing Apple's stock price to dip to its lowest value in over three months.

As of this writing Apple stock was down over 4 percent in Monday trading to around $195. The company hasn't seen its stock below $200 since late July.

Lumentum has lowered a net revenue forecast from $405-430 million to $335-355 million, with earnings per share sliding from $1.60-1.75 to $1.15-1.34. Three analysts cited by Reuters suggested that this points to a reduction of 18 million to 20 million iPhones. Alternately Apple may simply have stockpiled too much inventory from Lumentum, though that would still indicate soft iPhone sales.

Neither Lumentum nor Japan Display have specifically identified Apple as the cause of their problems, but the former attributed them to a customer that's "one of our largest" and buying "laser diodes for 3D sensing." Apple is believed to represent about 30 percent of Lumentum's business.

Japan Display simply mentioned lower demand from smartphone makers.

The nexus of worries about iPhone sales has been the iPhone XR. The device has sometimes been predicted to be the most popular iPhone model in the coming year, owing to its $749 entry price while sharing many features of the iPhone XS. Recently though there have been doubts about how well the phone will do, the latest from TF Securities analyst Ming-Chi Kuo, who on Monday slashed his 2019 unit estimates 30 percent to 70 million.