What just happened? TF International Securities analyst Ming-Chi Kuo in a research note published over the weekend slashed his first quarter iPhone shipment forecast by 10 percent due to the Wuhan coronavirus outbreak in China.

In the note, seen by CNBC, Kuo said they are cutting their shipment forecast down to 36 million to 40 million units for Q2 2020. Apple no longer reveals how many phones it ships per quarter but Kuo estimates that the Cupertino-based company moved roughly 38 million handsets during the first quarter of 2019.

Apple's stock appears to be unaffected by the note in early morning trading. As of writing, shares are valued at $311.71, a slight increase of 0.71 percent.

Apple over the weekend announced that out of an abundance of caution, it would be temporarily closing its stores and offices in mainland China through February 9 based on advice from leading health experts. The company's online store in China, however, will remain open.

Forecasting beyond Q1 is difficult, Kuo noted, due to the uncertainties of the coronavirus and consumer confidence.

Indeed, if the virus is quickly contained and mitigated, the effects on manufacturing and consumer purchasing could be minimal. Should it play out for a bit longer, manufacturing efforts could take a further hit and consumers may be more leery about making frivolous purchases.