Qualcomm stock falls as backed up Apple iPhone inventory contributes to weak outlook

Qualcomm Inc. shares dropped Thursday after Wall Street digested a surprise weakness in sales to Apple Inc. for its iPhone and margin lows not seen in nearly three years.

Qualcomm QCOM shares fell more than 8% to an intraday low of $103.50 in morning trading, and were last down 6.8%, on track for their worst day since Nov. 3 when shares closed down 7.7%.

Shares…