Apple (AAPL -1.22%) investors have been struggling to understand the company's rock-bottom valuation post-earnings. In spite of its history of heady growth in recent years, amid uncertainty over its margins and remaining high-end smartphone growth, Apple now trades at a P/E around 10.4. That figures falls to 7.5 when backing out its significant cash hoard.

In the video below, Fool senior technology analyst Eric Bleeker discusses where investors are paying up for mobile growth. He notes that Qualcomm (QCOM -2.36%) is the best proxy for mobile devices as it has licensing agreements to collect a percentage of sales on nearly all smartphones. What are markets willing to pay for a company with exposure to all facets of the smartphone space? In Qualcomm's case, that's 18 times earnings. A more dramatic case of extreme valuations for companies with broad mobile exposure would be Arm Holdings' (ARMH) P/E ratio near 80!

Eric discusses how Qualcomm's P/E ratio is illustrative of what investors would pay for Apple if the company were to demonstrate that it'll continue finding new mobile growth avenues in the coming years. That could come from outsized tablet growth or from extending the iPhone product line and picking up share across the globe.