The S&P 500 has shot up by more than 75% since the stock market's coronavirus-induced crash hit bottom on March 23. Almost a year later, the upswing is continuing, but investors shouldn't ignore the possibility that another major correction could strike sometime soon.

That isn't to imply that one should sell out of stocks in fear of such an occurrence. But savvy investors should be prepared to take advantage of such an opportunity if it arrives, with a watch list of companies they would want to buy on the dip.

Three hot stocks -- Apple (AAPL -1.22%), Micron Technology (MU -4.61%), and NVIDIA (NVDA -10.01%) -- could turn into particularly attractive buys if a broad market crash sends them tumbling. Let's take a look at why you should keep an eye on them.

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1. The iPhone upgrade supercycle could unlock terrific growth for Apple

The revenue-generating machine that is Apple has shifted into a higher gear thanks to the debut of its 5G-enabled iPhone 12 models. The tech giant's revenue soared 21% year over year in its fiscal first quarter (which ended Dec. 26) to a record $111 billion, and earnings jumped 35% to $1.68 per share. Analysts expect Apple's revenue to grow by 21% this fiscal year to $333.6 billion, while earnings per share are projected to increase nearly 36% to $4.45 per share.

The company could easily hit those estimates this year, as iPhone sales are expected to improve substantially over 2020 levels. Daniel Ives of Wedbush Securities (via AppleInsider) predicts that Apple could ship a record 250 million iPhones in 2021 -- surpassing the 231 million units it shipped in 2015 -- driven by the intense demand for the iPhone 12 models.

Ives' projection is based on the estimate that there are 350 million iPhones in an upgrade window, and the 5G-enabled offerings from Apple will kick off a massive upgrade cycle as consumers will want to make the jump to the new, much-faster, wireless standard. This should pave the way for solid top-line growth at Apple, as the iPhone produced nearly 59% of its total revenue last quarter. What's more, Apple's iPhone revenue shot up 17% year over year during the quarter despite the new devices reaching the market later in the season than usual.

The iPhone 12's success catapulted Apple to the top of the smartphone sales chart in 2020's fourth quarter, according to IDC. It looks all set to stay there thanks to competitively priced devices that could help it corner a big slice of the booming 5G smartphone market and unlock a multiyear growth opportunity.

Apple stock currently trades at 36.5 times trailing earnings. That's expensive considering its five-year average price-to-earnings (P/E) multiple of 19.4, but investors could get a better deal on Apple shares in the event of a stock market crash.

2. Tailwinds for Micron Technology

Micron Technology is being lifted by favorable trends in the memory market, where a shortage of chips is boosting prices. The contract price of dynamic random access memory (DRAM) increased 5% year over year in January -- the first month those prices had risen since May. Further incremental growth appears to be in the offing, based on the spot pricing trends.

DRAMeXchange reports that the spot price of the benchmark 8 GB DDR4 DRAM chip jumped to $3.93 earlier in February, up nearly 55% from the spot price of $2.54 in August. Higher DRAM spot prices should ideally lead to an increase in contract prices, which are negotiated on a monthly or quarterly basis.

Micron gets 70% of its revenue from selling DRAM chips, so the uptrend in this market bodes well for the memory specialist. More importantly, improving memory prices are already having a positive impact on the company's financial performance. Analysts expect Micron's revenue to increase nearly 17% in the current fiscal year, and they forecast a jump of almost 26% in the next one.

However, Micron's recent rally has made the stock expensive by the common valuation metrics. Its trailing P/E of 33.2 is more than double its five-year average of 16.4. But because of the anticipated strong earnings growth, its forward P/E is just 21.

MU EPS Estimates for 2 Fiscal Years Ahead Chart

MU EPS Estimates for 2 Fiscal Years Ahead data by YCharts

All of this makes Micron Technology worth buying if a crash pulls its share price back down to a better valuation. Such a decline would likely be temporary, as the supply-and-demand dynamics in the memory market are poised to send the stock higher in the long run.

3. NVIDIA is a solid long-term bet

Graphics chip powerhouse NVIDIA has been the biggest recent gainer of the three stocks discussed in this piece, and not surprisingly, it is the most expensive based on common valuation metrics as well. The stock trades at nearly 98 times trailing earnings. And even its forward P/E of nearly 53 is rich when compared to its five-year average forward earnings multiple of 36.

But that valuation seems justified considering NVIDIA's impressive pace of growth. The good part is that the company looks capable of maintaining its momentum in 2021 thanks to strong demand from the video gaming and data center markets for its graphics cards.

Indeed, the company is finding it difficult to keep up with the overwhelming demand for its latest graphics cards, but it is still taking market share away from rival Advanced Micro Devices. NVIDIA won a dominant 80% share of the discrete GPU (graphics processing unit) market in 2020's third quarter, according to Jon Peddie Research. That was a 4 percentage point increase over 2019's third quarter.

NVIDIA's strong position in the graphics card market should help it sustain its high pace of revenue growth. That's because a huge installed base of graphics card users are waiting to upgrade to new GPUs so that they can play the latest, most graphics-intensive games. NVIDIA is working to scale up its supply chain to meet the demand, though it should be noted that the company will benefit from higher GPU prices caused by the supply shortage in the meantime.

Given all that, the video gaming business that supplied 48% of NVIDIA's revenue last quarter is unlikely to lose steam even after its terrific showing in 2020.

Similarly, the company's data center business is also benefiting from a secular tailwind in the form of the growing data center accelerator market. The demand for data center accelerators is expected to increase substantially in the coming years, and NVIDIA is going after that opportunity with new products that could add billions of dollars to its annual revenue.

As such, any notable dip in NVIDIA's stock price in the event of a broader market slide will give investors the opportunity to buy a hot tech stock at a more reasonable valuation.