After the stock market crashed earlier this year, I went on a buying frenzy. And I'm glad I did. Every stock I bought has delivered positive returns so far, and most of them have been big winners.

But I've slowed down my buying activity considerably in recent weeks. With the overall stock market resurgence, there aren't as many beaten-down bargains to be found. That doesn't mean, though, that there aren't still stocks worth buying. 

What's the one stock I'd buy right now above all others? My pick is a stock that I already own: Amazon (NASDAQ:AMZN).

Finger pointing to a chalk drawing of a light bulb with a dollar sign that's separated from other light bulbs without dollar signs

Image source: Getty Images.

Battling my inner pessimist

Let me state right off the bat that I think there are growth stocks that will almost certainly outperform Amazon over the next decade. I like several smaller companies that have innovative products and large market opportunities. So why did I go with Amazon as my top pick?

I'm an optimist by nature. However, I do have an inner pessimist that emerges every now and then -- and it's front and center right now. The number of COVID-19 cases are soaring in many states, and hospitals are running out of ICU rooms. All of this is happening during the heat of summer, the season when viruses like the flu don't spread as much. My inner pessimist tells me to brace for a rough fall and winter.

Like nearly every American, I definitely don't want a return of lockdowns and shelter-in-place orders. However, it seems like a realistic possibility, considering how things stand in much of the country. Amazon ranks as one of the stocks that would benefit if there's a severe second wave (or worsening of the first wave) of COVID-19 outbreaks.

As a long-term investor, I try not to focus too much on short-term headwinds. However, it's still hard to invest a lot of money in a stock that I think could very well sink in the near future. I'd rather scoop up shares when they're priced at a discount. But since I expect that Amazon will be largely resilient to another major market pullback, buying it helps me win in the battle against my inner pessimist.

Checking off the most important boxes

Even better, though, Amazon checks off the most important boxes that I look for in a stock. These include a healthy financial position, a strong moat, and multiple paths to generate future growth.

Healthy financial position? Amazon generated revenue of nearly $300 billion over the last 12 months with profits of more than $10.5 billion. Sure, the company's response to the COVID-19 pandemic will curtail earnings growth over the short run. But that isn't concerning, in my view.

Amazon's moat remains one of the strongest you'll find. The company dominates in the e-commerce market. It's the leader in the cloud-hosting market. I fully expect that Amazon will continue to deliver solid growth on both fronts.

But I also look for Amazon to become a bigger player in new markets. Put healthcare at the top of the list. My hunch is that Amazon will expand its online pharmacy efforts and potentially move into the telehealth market, as well. The company is also dipping its toes into the waters of the self-driving car technology arena with its acquisition of Zoox.

Not a perfect stock

Don't think I'm just a card-carrying member of the Amazon fan club. I recognize that it's not a perfect stock. Such a stock doesn't exist.

Amazon's valuation appears absurdly expensive, at least when you look at earnings-based multiples. The company has also grown so big that it's a perennial target of politicians and antitrust agencies.

However, I don't think earnings-based multiples are all that useful with Amazon because of its continual investment of profits into new areas. And while it's certainly possible that Amazon could one day be split up by regulators, I think the sum of the parts would be worth more than Amazon's current market cap.

My view is that Amazon is a good option if you're concerned (as I am) that the COVID-19 pandemic could worsen in the near future. It also offers strong long-term growth prospects, thanks to its financial strength, moat, and aggressive expansion into new markets. That's close enough to perfect for me.