Apple Inc. (AAPL - Get Report) shares are tumbling, along with the rest of the U.S. stock market Wednesday, bringing the tech behemoth into bear market territory. 

The stock was falling 2.3% on Wednesday around noontime to a share price of $187.83 and briefly dropped below $186.80, which would be a 20% drop from its most recent all-time high of $232.07, signaling a bear market. 

Late on Monday, Goldman Sachs cut its price target for Apple from $240 a share to $209 after one of its suppliers, Lumentum Holdings Inc. (LITE - Get Report) said one of its key customers requested a shipments reduction. Apple uses Lumentum's components for its Face ID facial recognition system on the iPhone X, making it highly likely that it was Apple that requested the reduction.

Apple planning to buy fewer parts from Lumentum would signify it will sell fewer iPhones going forward than initially expected. Apple said in its most recent quarter that will no longer give unit sales figures for the iPhone and iPad as it focuses on overall revenues, but a material reduction in units would still reduce revenue expectations.

"We are reducing our iPhone units estimate with this note following Lumentum's large negative pre-announcement on 11/12," Goldman analyst Rod Hall wrote in his note. He added, "LITE reduced its Dec qtr revenue guidance by 17% as a large 3D sensing customer adjusted demand." 

"We infer from LITE's pre-announcement that the likely customer was Apple," Hall wrote. 

Hall reduced his revenue outlook for Apple in 2019 by 3.5% and now expects earnings-per-share for the year to be $13.00, down from his previous expectation of $13.44. 

Zev Fima, research analyst for Jim Cramer's Action Alerts Plus portfolio, which owns Apple, said that "we remain of the opinion that Apple is a stock to be owned, not traded. While the rest of Wall Street is focused on unit sales, we remain focused on the growth in Services, which provides favorable margins and a recurring revenue stream, which we continue to believe will ultimately justify an expanded valuation multiple."

Despite the recent decline, Apple shares are still up almost 11% this year. 

Apple is a holding in Jim Cramer's Action Alerts PLUS member club . Want to be alerted before Jim Cramer buys or sells AAPL? Learn more now.