Apple's top iPhone supplier will reportedly reduce working hours during the week-long Chinese New Year holiday, which could suggest lower demand. In fact, Apple investors are now dealing with fewer shipments of the company's smartphones, average forecasts from suppliers, and higher inventories of iPhone 6S and 6S Plus units.

Japanese daily newspaper Nikkei reported on January 6, Wednesday, that iPhone models' output would be cut by around 30 percent during Q1 of this year, based on reports from parts suppliers, according to Reuters. Apple shares fell 2.5 percent, and the parts suppliers' stock prices also closed lower.

The Wall Street Journal has claimed Apple has recently cut iPhone orders to suppliers. It has reportedly taken that action for several months, according to Engadget.

This year's Lunar New Year will happen on February 8. iPhone supplier Foxconn usually provides overtime work and triple overtime pay  for its workers, but reportedly this year the company's employees will get a standard holiday break.

Foxconn is a Taiwan-based company that assembles the newest iPhone models in China. Its payroll there includes hundreds of thousands of workers.

In December demand slowed for iPhone semiconductors and casings. However, analysts questioned if a global slowdown was taking place.

Apple also announced on Wednesday that consumers spent more than $1.1 billion on apps and in-app purchases during the two-week period ending on January 3. It was a sales record during the holiday season.

Reuters reported that around one-third of analysts it tracks have lowered their 2016 estimates for Apple. The average revenue forecast is a 4 percent increase, compared to the 28 percent increase for the fiscal year that ended last September.    

It is unclear what is causing Apple's drop in iPhone orders. Some theories include overly high production, China's economic slow-down, and the iPhone 6S only tweaking the iPhone 6.