As you've probably learned one way or another over the past two months, stock market corrections, and even bear markets (i.e., declines of at least 20% from a recent high), are an inevitable part of the investing cycle.

Generally speaking, we never know ahead of time when a correction will occur, how long it'll last, or how steep it'll get. But we do know that buying stocks during periods of correction has always been a smart move. That's because every single correction and bear market in history has eventually been put into the rearview mirror by a bull market rally. Thus, the more the stock market falls, the greater the opportunity for long-term investors to benefit.

The coronavirus disease stock market crash, which pushed the benchmark S&P 500 down by 34% in just 33 calendar days, represented one heck of an opportunity for investors to pick up high-quality businesses on the cheap. When the next stock market crash rears its head, or if the COVID-19 plunge resumes, be prepared to scoop up the following five stocks.

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Image source: Getty Images.

Alphabet

There's little question that COVID-19 mitigation measures, which include the shutdown of nonessential businesses, are going to hurt the advertising industry. But a few months of pain, or perhaps even a year, are no reason to give up on the most dominant company in the ad realm, Alphabet (NASDAQ:GOOG)(NASDAQ:GOOGL).

Alphabet's key asset is the Google search engine, which according to Global Stats, accounted for 92% of all worldwide search market share in March 2020.  With such a dominant search platform, Alphabet has little issue commanding premium price points for ad placement, and will likely see its traffic acquisition costs level out over time. This is a formula for higher operating margins from its core sales driver.

But it's not just Google search that's driving the excitement. Google Cloud sales have more than doubled since 2017, while YouTube ad revenue is up 86% over the same period. Cloud margins are of particular interest because they're much juicier than traditional ad margins. As Google Cloud grows into a larger percentage of total sales, Alphabet's cash flow could really soar.

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Intuitive Surgical

In the healthcare space, a company I can't stop beating the drum about is robotic surgical system developer Intuitive Surgical (NASDAQ:ISRG). If you can look past the near-term disruption associated with delayed elective procedures due to the coronavirus pandemic, you'll see a company with a long-term double-digit growth rate.

The amazing thing about Intuitive Surgical is that its operating margins are going to continue improving over time. That's because it's built on the razor-and-blades business model. It first gets hospitals and surgical centers hooked through the purchase of its da Vinci surgical system, which is pricey but has generally low margins since it's a complex system to build. The "blades" in this case are the instruments sold with each surgical procedure, as well as the servicing performed to keep these machines operating well. As the number of installed da Vinci systems grows, the percentage of sales derived from these higher-margin segments will increase.

This is also a company with plenty of opportunity to expand the use of its surgical system, which is currently dominant in urology and gynecology procedures. Management anticipates market share expansion into colorectal, thoracic, and general soft tissue surgery in the years to come.

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Image source: Amazon.

Amazon.com

If the coronavirus stock market crash has taught us anything, it's that Amazon.com (NASDAQ:AMZN) has become an integral source of our consumption. Despite weakness in early March, shares of Amazon wound up hitting a fresh all-time high last week.

A lot of folks favor Amazon for its very visible and highly dominant e-commerce platform. There's no question that e-commerce generates the bulk of Amazon's revenue, or that the more than 150 million Prime members help to supplement what are usually pretty anemic retail margins. With Americans on stay-at-home orders from their respective state governors, Amazon will likely see holiday-season-level buying throughout the first quarter.

But like Alphabet, the real allure here is the faster-growing cloud-service segment, Amazon Web Services (AWS). Despite accounting for 12.5% of total sales in 2019, AWS was responsible for 63% of the $14.5 billion the company generated in operating income. Since cloud margins are much, much juicier than retail margins, Amazon can expect a cash flow explosion in the years to come

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Mastercard

I can imagine that the idea of buying into a payment processor like Mastercard (NYSE:MA) during a stock market crash probably doesn't sound smart. After all, consumer spending is likely to decline as a result of adverse economic conditions. But payment processor Mastercard has proved exceptionally resilient over many decades.

It currently occupies the No. 2 spot in terms of credit card market share by network purchase volume in the U.S., which isn't a bad spot to be in considering how dependent the U.S. economy is on consumption. Between 2009 and 2018, the purchase volume traversing Mastercard's U.S. network surged from $477 billion to $811 billion, with the company also boosting its U.S. debit-card market share by roughly 7 percentage points to 29%. 

Mastercard also has plenty of opportunity in overseas markets, with an estimated 85% of transactions still being conducted in cash. Rolling out infrastructure to new markets may be costly up front, but Mastercard's 48% profit margin over the trailing-12-month period is tough to overlook.

As one last note, Mastercard is a payment facilitator and not a lender. This means it's not directly exposed to credit delinquencies during periods of economic contraction, which is another reason its margins are so robust.

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Image source: Getty Images.

ExxonMobil

Another smart stock to buy during a stock market crash is integrated oil and gas giant ExxonMobil (NYSE:XOM). Similar to Mastercard, there's no question that ExxonMobil is going to see serious short-term disruption during periods of recession as crude demand falls. But the company's diverse operations are a big reason it can easily weather the storm.

Although ExxonMobil generates most of its profits from its upstream operations, which includes drilling and exploration, its downstream segment helps to hedge its business during periods of crude-pricing weakness. These downstream operations (e.g., refineries and petrochemical plants) are able to purchase crude at a much lower cost during periods of recession. As costs for petroleum-based products decline, demand among consumers and enterprises usually rises, allowing these downstream operations to shine.

ExxonMobil also has the ability to reduce its outlays significantly to improve its cash flow. It reduced its capital expenditure budget for 2020 by up to $10 billion in recent weeks, and it could, if necessary, save more than $14.6 billion annually by shelving its dividend. While I doubt it comes to that, the point is that ExxonMobil has more levers it can pull than most other oil stocks, and it's set to benefit once the COVID-19 pandemic has passed.