Investors were in for a bit of a shock earlier this week. On Monday, Feb. 24, all three stock market indexes put up some of their largest point declines in history. The tech-heavy Nasdaq Composite fell 355 points, the broad-based S&P 500 sank almost 112 points, and the Dow Jones Industrial Average logged its third-largest point decline in its 123-year history at 1,031 points.

The culprit was (and remains) growing fear surrounding COVID-19, the lung-focused novel coronavirus that originated in Wuhan, within China's Hubei province. What has the attention of Wall Street is the outbreak of the illness in South Korea, Italy, and Iran over the past weekend. It's looking less likely that COVID-19 will be contained, leading to the possibility that the World Health Organization could declare a true pandemic.

A person writing and circling the word buy underneath a dip in a stock chart.

Image source: Getty Images.

The issue at hand is that COVID-19 not only puts lives at stake, but it can also bring key supply chains and countrywide growth to a grinding halt. China, which is the world's second-largest country by gross domestic product, has seen extended business stoppages in certain regions of the country, with many analysts forecasting a negative first-quarter GDP impact. As China is the second-largest economy in the world, the ripple effects of this weakness are bound to be felt by others.

Then again, history has shown that illness-based market downturns tend to be modest and short-lived. The downside moves in the stock market associated with the likes of the avian flu, Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and Ebola totaled just 6% to 12%, and were often complete within a matter of weeks or months. In other words, this correction is almost certainly an opportunity to buy great companies for a fair price.

In my view, if you don't consider adding the following four top stocks to your portfolio on any coronavirus weakness, you're going to regret it.

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Image source: Amazon.com.

Amazon.com

Just when you thought the holidays were over, you're getting yet another chance to buy into a company at a discount that I believe will be the first to hit the $2 trillion market cap plateau.

Shares of e-commerce giant Amazon.com (NASDAQ:AMZN) have shed close to 8% of their value in a little over a three-day stretch. But this doesn't make a lot of sense, especially given that cloud-computing, not retail, is Amazon's future. Sure, there's always the potential for COVID-19 to reduce retail consumption in the short term, but the bulk of Amazon's margins and operating income are being derived from Amazon Web Services (AWS). Remember, AWS accounted for $9.2 billion of the $14.5 billion in operating income Amazon recognized in 2019, yet was responsible for only 12.5% of net sales. As AWS grows into a larger component of total sales, Amazon's cash flow is going to explode higher. 

Speaking of cash flow, don't forget that Amazon has traditionally been valued at a multiple of 23 to 37 times its cash flow per share over the trailing decade. Yet between 2019 and 2023, Wall Street foresees cash flow per share catapulting from $76 to $192. If Amazon simply keeps its valuation within range, this could easily be a $5,000 stock within four years.

Two CVS pharmacists working on a computer.

Image source: CVS Health.

CVS Health

One of the bigger head-scratchers out there is why healthcare companies sell off when severe illnesses rear their head. After all, the logical thinking here is that increased emphasis would be placed on drug development and healthcare products during such times. That's why I'm eyeing pharmacy chain CVS Health (NYSE:CVS).

Though the COVID-19 scare may lead to increased foot traffic in its stores -- the company is planning to open 1,500 HealthHUB health clinics around the country by 2021 -- it's the potential for juicier pharmacy sales that has me intrigued. CVS generates much better margins from its pharmacies than front-end sales. 

What's more, CVS Health's acquisition of health insurer Aetna, which closed in 2018, should continue to pay dividends. Health scares tend to provide a wake-up call to the uninsured to become insured. Couple this with the fact that cost synergies from the Aetna acquisition should grow in 2020 from what they were in 2019, and CVS Health is looking mighty cheap. How inexpensive, you ask? How about a little over 9 times this year's projected earnings per share for a company that's average a trailing price-to-earnings ratio of 19 over the past five years.

An up-close view of a flowering cannabis plant growing in an indoor commercial farm.

Image source: Getty Images.

Innovative Industrial Properties

No, your eyes aren't deceiving you, and yes, you should have a cannabis stock on your buy list as coronavirus fears pick up.

To be perfectly clear, Innovative Industrial Properties (NYSE:IIPR) isn't your typical marijuana stock. It's actually a pot-focused real estate investment trust (REIT). In simple terms, it acquires marijuana cultivation farms and processing sites, then leases these assets out for extended periods of time. This allows the company to pocket the rental income from these assets, as well as bask in modest organic growth by passing along annual rental increases and collecting a property management fee tied to this increasing rental base. Being set up as a REIT de-risks Innovative Industrial Properties significantly, relative to other pot stocks, as well as allows it to pay out a nearly 4% yield.

Innovative Industrial Properties also continues to benefit from the lack of access to basic banking services for U.S.-focused cannabis companies. As long as marijuana remains a federally illicit substance, this company's ability to be a sale-leaseback agreement facilitator with vertically integrated multistate operators puts it in a very advantageous position.

Two gold ingots placed side by side.

Image source: Getty Images.

SSR Mining

When fear abounds, investors typically rush into safe-haven investments, such as bonds or gold. But in recent weeks, gold-mining stocks haven't fared as well. While there is some merit to the idea that weakness in China could reduce demand in the short-term, it ignores just how much extra profit gold miners like SSR Mining (NASDAQ:SSRM) could bring in over the next year, or likely longer.

On a macro level, factors like inflation and fear aren't the major driving force behind the current gold rally. Instead, it's sinking global yields driving this rally. Earlier this week, the U.S. 10-year Treasury bond tied an all-time closing low yield of 1.37%. If bond yields can't even top inflation, investors are liable to turn to precious metals as a better store of value. This is what, in my view, could push gold well past $2,000 an ounce within a year.

As for SSR Mining, it's one of the most efficient mid-tier players. Expansion at the flagship Marigold mine in Nevada should allow for a 20% boost to production by 2021 (this equates to an extra 45,000 ounces of gold produced per year, relative to what was produced in 2019). Meanwhile, the Canadian Seabee mine has produced record output every year since being acquired in 2016. If gold were to hold $1,650 an ounce, and production hits 265,000 ounces annually at Marigold and say 115,000 ounces at Seabee, SSR Mining's annual revenue would jump by around $100 million, which I suspect could add $30 million to $40 million in net income. Don't overlook this gold stock