The iPhone 5 is the single most important factor investors should be focusing on when Apple (AAPL -1.22%) reports after the close. Last quarter, iPhone revenues made up over 47% of total revenue, and since iPhone 5 commands a 68% gross profit margin, it's a huge driver of profitability for the company. It remains to be seen if Apple's prized possession will deliver the goods and push average selling prices higher for Team Cupertino. The fear is that users have been upgrading to iPhone 4/4S models over the iPhone 5, which would drive average selling prices lower for the iPhone family. There could be a number of reasons why Apple would miss on its iPhone estimates, but two prominent headwinds that the iPhone 5 faces are that it's cost prohibitive for unsubsidized smartphone users, and that the world's 4G LTE network infrastructure is currently lacking.

The fact of the matter is that the Apple economy is so large that an iPhone miss could be detrimental to its suppliers and perhaps even the technology sector as a whole. That said, I'll be focusing on some of the key component suppliers for the iPhone 5 that could be at peripheral risk of an iPhone 5 miss.

Qualcomm (QCOM -2.36%)
Although more diversified than other Apple suppliers, Qualcomm provides the iPhone 5 with its 4G LTE modem, as well as other wireless and power components. It's estimated that these components are worth $34 in revenue to Qualcomm for each iPhone 5. If Apple sells 45 million iPhones, the low end of expectations, we're talking about an opportunity that could be worth as much as $1.5 billion for Qualcomm, assuming only iPhone 5s were sold. Last quarter, Qualcomm earned $4.9 billion in revenue, implying that the iPhone 5 has the potential to be worth up to 30% of Qualcomm's quarterly revenue. Obviously, not all iPhone sales will be iPhone 5s, but this goes to show you how much of Qualcomm's business could be at risk from the reception of a single product.

Cirrus Logic (CRUS -1.48%)
Cirrus supplies Apple with audio components that are used in the iPhone 5. Last quarter, Cirrus reported an earnings beat and raised guidance as a result of iPhone 5 demand and cited that it was heavily backlogged. At the time, shares traded at more than $40 a share, $11 more than where they sit today. The risk with this company stems from the fact that a whopping 79% of Cirrus' revenue comes from Apple. If there's any sort of iPhone 5 softness, I fully expect Cirrus shares to get punished.

Micron Technology (MU -4.61%)
Micron's recent acquisition of Elpida, a bankrupt Japanese memory supplier, landed it a spot in the iPhone 5. According to iSuppli, the iPhone's 5 DRAM component is estimated to cost $10.45 per unit, giving Micron a potential $470 million opportunity, assuming 45 million iPhone 5s were sold. Considering that Micron itself has lost $2.53 billion over the last five years and just acquired a bankrupt company for $2.2 billion, there's a sense of urgency for its business prospects to improve. Although an iPhone 5 home run wouldn't be enough to ease investor concerns, a miss would likely add to the negativity to Micron's business outlook.

Nuance Communications (NUAN)
Nuance helps power Siri, Apple's voice-activated assistant, and provides support for App Store developers to leverage its voice-recognition technology. For Nuance, it's about how iPhone 4S and 5 activations fared, rather than just iPhone 5 sales, as Siri is featured on both the iPhone 4S and 5. However, Nuance is well diversified company with deep roots in Android, and its mobile division made up 31% of its total business last quarter.

The big day
In a few short hours, the world will know if Apple is still the greatest consumer technology company on the planet. Regardless of outcome, the report is likely to weigh heavily on the Apple supply chain. Of the four companies mentioned, Cirrus Logic is by far the most at risk, given that 79% of its revenue depends on Apple.