We all would love a market that rises nonstop. But we have to face facts: A market downturn will happen at some point down the road. The good news is we can prepare our portfolios for it. That means investing in a few names with strong earnings -- and companies that can grow revenue even when economic times are tough.

Whether you're a cautious or aggressive investor, investing in these sorts of companies before a downturn is a smart move. Here, I'll talk about a retailer, a big pharmaceutical company, and the leader in the robotic surgery market. Let's take a closer look at each one.

An investor studies something on a computer in a home office setting.

Image source: Getty Images.

1. Target

You probably are wondering how a retailer could outperform when the market turns sour. After all, if the economy doesn't look too great and/or confidence is down, consumers probably won't go out on many shopping sprees. That's true. But Target (TGT 1.28%) has built strength in areas that will continue to thrive even in tough times.

Here, I'm referring to essentials, grocery, and owned brands focused on the basics. For example, Target in one year grew its Good & Gather food brand and its All in Motion activewear brand to more than $1 billion in revenue each. People flock to Target for these kinds of items at all times. The company saw this during the worst of the coronavirus pandemic. The result? Target's sales growth in 2020 totaled more than the past 11 years combined.

Target's selection of pickup and delivery options also keep customers coming back. And the company is investing $4 billion annually to keep stores fresh and optimize fulfillment. Target's strategy is paying off. It's return on invested capital (ROIC) gained sharply last year and remains high.

TGT Return on Invested Capital Chart

TGT Return on Invested Capital data by YCharts

2. Pfizer

Demand for drugmakers' products usually doesn't suffer during market downturns. That's why it's a great idea to add a solid player with many blockbusters to your portfolio. Pfizer (PFE -0.12%) fits the bill. The company sells eight blockbuster products. That includes the world's most sought-after product right now: the coronavirus vaccine.

Other top sellers include blood thinner Eliquis and oncology drug Ibrance. Of course, drug patents only hold up for so long. And several of Pfizer's biggest drugs will face generic competition in a few years. But the company has 100 projects in the pipeline. So it's likely Pfizer will be able to renew its offerings -- and keep up revenue growth.

Pfizer's particularly interesting now because it's trading at only about 10 times forward earnings estimates. At the same time, it's a different company than it was a year ago. It's spun off Upjohn -- so that business won't weigh on earnings. And the coronavirus vaccine is set to generate more than $33 billion in revenue this year. This looks like a good time to get in on the stock.

3. Intuitive Surgical

Intuitive Surgical (ISRG -0.41%) commercializes the Da Vinci robotic surgery system. It's widely used by surgeons in minimally invasive procedures. And with this, Intuitive holds nearly 80% of the robotic surgery market, according to BIS Research.

Intuitive makes its money by selling and leasing Da Vinci systems as well as by selling instruments and accessories and services. In fact, instruments and accessories generate the most quarterly revenue for the company. This area represented 53% of Intuitive's total third-quarter revenue. This is important because it provides a steady stream of revenue as hospitals perform surgeries with Intuitive's equipment.

Annual revenue has climbed for most of the past 15 years -- even in market downturns, surgeries must continue. The coronavirus pandemic was an exception. That's because, during the worst of the pandemic, hospitals postponed many surgeries to focus on COVID-19 patients. The impact was temporary, however. Intuitive reported a 30% increase in third-quarter revenue and a 20% increase in Da Vinci procedures.

Another sign of Intuitive's health: ROIC and free cash flow are rising once again.

ISRG Return on Invested Capital Chart

ISRG Return on Invested Capital data by YCharts

Intuitive recently completed a three-for-one stock split. This is positive because it makes it easier for investors with smaller budgets to invest in the stock. So, it opens investment up to a wider audience. Now is a good time to get in on this market leader -- and hold on through the next market downturn and beyond.