Skyfall! Apple's stock breaks 3 key levels

Investors wondering how low Apple (AAPL) stock can go are having to lower their expectations even more.

Shares of the gadget-maker Monday are down $2.68, or 2.2%, to $118.72 — breaking below three key support levels the legions of bullish investors have hoped would hold. The stock is being pressured by concerns economic slowing in China could hurt what's turned into the biggest growth market for Apple's high-priced smartphone in addition to data showing increased market saturation of smartphones in developed nations.

The drop in Apple's stock is noteworthy because it violates a number of key levels watched by investors, including:

* 10% correction level. Shares of Apple are down down 10.9% from their highest point in a year — which places the stock squarely in what's considered to be a correction. The unofficial definition of a correction is a 10% or greater drop from a recent high. Shares of Apple hit a 52-week (and all-time) high on $134.54 on April 28. The stock has subsequently hit that level — and failed to move higher — three times now. This indicates there's a big block of investors waiting to sell once the stock gets to that level. Apple shares are still up 7.3% this year - but they had been up as much as 22%.

* Break in the 200-day moving average. Apple's stock price takes it below $120.87 — which is an important price level of support watched by investors. That's the average price investors have paid for the stock over the past 200 trading days. By breaking below that level, the average investor who bought shares of Apple over the past year - is now underwater. Investors look to the 200-day moving average as a benchmark of longer-term trends, and a break below the 200-day moving average is viewed as a bad sign. Apple hasn't broken its 200-day moving average since September 2013.

* The $120 level.  Investors were hoping the $120 price level would serve as a floor for Apple. Seeing the stock cut through with little resistance is a bit of a cautionary sign. When Apple shares sunk into the danger zone July 9 and fell into a correction last time, they finally found buying support at about this level. Back on July 9, when fears about China slowing and disappointment over the Watch heated up, buyers stepped up and overwhelmed the sellers.

But while the market is sending a message it's getting cautious on Apple, Steven Milunovich at UBS said the caution is overdone. Apple can still boost iPhone shipments in fiscal 2016, Milunovich says, as he boosted his shipment target from 232 million to 245 million. He also boosted his earnings per share estimate to $10.32 from $9.94. He has a $150 a share price target on the stock

Milunovich agrees the iPhone is on an upgrade cycle now that so many people own a model already. He says that two-thirds of iPhone shipments are upgrades. But he thinks there could still be 15% growth in upgrades in the fiscal year — based on the idea that 76% of iPhone users will have upgraded. "The iPhone does have legs," he says.

Investors watching the stock fall — hope these legs start moving soon.