Is the iPhone 6S a smash hit? Apple may offer clues Tuesday

The company's fiscal fourth-quarter results will reflect just two weeks of new iPhone sales but will still hint at the popularity of the new smartphones.

Apple reports its latest quarterly results on Tuesday. But let's face it, all anyone really cares about is how the new iPhones did.

Preorders for the iPhone 6S and iPhone 6S Pluskicked off September 12, and the company's fiscal fourth quarter ended September 26. This means that Apple cannot offer a full quarter's worth of results Tuesday and that industry watchers are instead anxiously awaiting the sales forecast for the current quarter.

Apple doesn't provide estimates for its iPhone sales, but it's easy to draw conclusions from its revenue forecast because smartphones now represent about two-thirds of its sales. Those numbers and potentially a few candid comments from Apple's executives could offer up some clues.

The hints will indicate how well the new iPhones are expected to sell in the critical holiday shopping quarter. More importantly, they will help answer the question of whether the Cupertino, California, company and its iPhones have lost a bit of their swagger as consumer enthusiasm for smartphones cools.

The worry is Apple won't sell as many smartphones as it did the year before. That fear isn't unfounded. The entire smartphone market is slowing, and China, a key market for the company, has faced volatility in recent months. One-time highfliers Samsung and HTC have struggled, and it's unclear whether Apple will get dragged down with them.