For 18 months, investors have enjoyed an historic bounce-back rally in the broad-based S&P 500. Since hitting its bear-market bottom in March 2020, the widely followed index has doubled.

However, crashes and corrections are a normal part of investing in the greatest wealth creator on the planet. This past Monday, Sept. 20, the S&P 500 navigated its way through its worst single-session performance in four months. While it's impossible to know if this is the beginning of a full-fledged correction or simply an emotion-driven short-term sell-off, one thing is for certain: A tumbling market is always an opportune time to put your money to work in brand-name, time-tested companies.

If the market were to continue tumbling in the days or weeks that lie ahead, long-term investors should consider buying the following five brand-name stocks hand over fist.

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

Image source: Getty Images.

Mastercard

History has shown that any dip in payment-processing giant Mastercard (MA 0.60%) is an opportunity for investors to scoop up this high-margin company at a discount.

Mastercard is a cyclical company that benefits from spending a lot of its time in the sun. Although recessions and contractions are a normal part of the economic cycle, periods of economic expansion often last years. Mastercard is able to take advantage of consumer and enterprise spending during these long-winded periods of expansion. It's a simple numbers game that's always favored Mastercard.

Another reason it's such a successful company is that it avoids lending. Though Mastercard is giving up the opportunity to generate interest income and fees as a lender, it's also avoiding the credit delinquencies that accompany inevitable recessions. Not having to set capital aside to cover these delinquencies is a big reason its profit margin is consistently north of 40%.

Mastercard is the clear-cut No. 2 payment processor in the U.S., the most prominent market for consumption in the world, and it offers a long runway for global expansion. If the market were to tumble, it's a no-brainer buy.

A Home Depot employee carrying a gallon of paint in each hand.

Image source: Home Depot.

Home Depot

It may not be the first brand-name stock that comes to mind when uncertainty rears its head on Wall Street, but do-it-yourself home-improvement chain Home Depot (HD -0.55%) is a really smart buy on any market weakness.

While you might get the impression that Home Depot is an entirely cyclical stock, the company has a means to hedge its bets, so to speak, in any economic environment. It obviously benefits during periods of expansion with strong commercial-client demand, but what's often overlooked is that home remodels become popular during periods of contraction. With fewer people moving during contractions or recessions, it creates the perfect scenario for homeowners to change things up.

Home Depot's aggressive investments in digitization should pay dividends, as well. Walk-in customers to its physical stores are still this company's bread and butter, but being able to integrate the physical and digital experience should result in faster sales growth and an overall better customer experience. There's no reason Home Depot can't maintain double-digit direct-to-consumer sales growth for the foreseeable future.

A silicon wafer die attach machine in action.

Image source: Getty Images.

Broadcom

Tech stock Broadcom (AVGO 1.14%) is another brand-name company investors can pile into if the stock market turns lower.

Although Broadcom's semiconductor solutions are used by a number of industries, smartphones have long been the company's primary revenue generator. The rollout of 5G wireless infrastructure is an especially big deal.

It's been roughly a decade since consumers and businesses have been offered a substantive upgrade in download speeds. This should lead to a multiyear smartphone replacement cycle that'll benefit Broadcom, which makes 5G chips and other accessories found in smartphones.

Beyond just wireless devices, Broadcom seems to be sitting on a veritable gold mine with businesses shifting more and more of their data into the cloud. The company provides connectivity and access chips to data centers, which are critical to storing this data.

Want one more reason to take the plunge? Broadcom's quarterly dividend has grown by more than 5,000% in under 11 years. With much of its production capacity booked months in advance and a 2.9% yield to boot, Broadcom can be your portfolio's rock in the tech space.

A lab technician using a pipette to place liquid samples into a row of test tubes.

Image source: Getty Images.

Bristol Myers Squibb

Pharmaceutical stocks are an excellent place to park your money if and when stock market volatility picks up. The brand-name drug stock to buy hand over fist, should the market keep falling, is Bristol Myers Squibb (BMY -0.22%).

What makes this company so special is its organic and acquisition-based growth. Beginning with the former, Bristol Myers is on track to rake in north of $10 billion from Eliquis this year. Eliquis is the world's leading oral anticoagulant and was developed in cooperation with Pfizer.

There's also cancer immunotherapy Opdivo, which is approved in 10 indications and is being examined in dozens of clinical trials as a monotherapy or combination treatment. Opdivo is already bringing in about $7 billion in annual sales.

On the acquisition front, Bristol Myers Squibb made waves by acquiring cancer and immunology drug developer Celgene in 2019. The crown jewel of this buyout was multiple myeloma drug Revlimid, which topped $12 billion in sales last year. A combination of label expansion, longer duration of use, improved cancer-screening diagnostics, and strong pricing power has helped Revlimid to double-digit annual growth for over a decade.

Being able to snag Bristol Myers Squibb at less than eight times forward-year earnings is an absolute steal.

An employee wearing a headset and speaking with a customer at her desk.

Image source: Getty Images.

Salesforce

Last but not least, opportunistic long-term investors can buy cloud-based customer relationship management (CRM) software provider Salesforce.com (CRM 1.92%) hand over fist if the market tumbles.

For those of you who might not be familiar with CRM software, it's used by businesses to enhance their customer relationships and expand sales. It can be used to oversee product and service issues, handle online marketing campaigns, and run predictive sales analyses.

Salesforce slides into the picture as the king of the mountain. It held just shy of 20% of the global CRM market share, based on revenue, as of the first half of 2020, per an IDC report. The next four competitors didn't even combine to equal Salesforce's market share. This places it at the center of a sustainable double-digit growth trend for consumer-facing businesses.

And like Bristol Myers, it's been an acquisition superstar. CEO Marc Benioff has overseen the earnings-accretive purchases of MuleSoft and Tableau, and recently completed the buyout of cloud-based enterprise communications platform Slack Technologies. Slack should help Salesforce cross-sell its solutions to small- and medium-sized businesses.

With Benioff calling for $50 billion in annual sales in five years, which is more than double the $21.3 billion reported in fiscal 2021, Salesforce checks all the boxes as a no-brainer buy.