When President Joe Biden took office on Jan. 20, 2021, he inherited one of the worst economic catastrophes in decades. The coronavirus disease 2019 (COVID-19) pandemic wreaked havoc on the U.S. and global economy, and it briefly sent the U.S. stock market into a tailspin.

However, a perfect storm could be brewing for equities under the Biden administration. The Federal Reserve has pledged to hold firm on historically low lending rates, while the White House is calling for trillions of dollars in additional spending. This abundant access to cheap capital is the perfect recipe for stocks to thrive in a rebounding economy.

If a Biden bull market does take shape, the following five unbeatable stocks would be the perfect companies to own.

A bull figurine next to a rapidly rising chart in a financial newspaper.

Image source: Getty Images.

Alphabet

Few stocks are more synonymous with the word "unbeatable" than Alphabet (NASDAQ:GOOGL)(NASDAQ:GOOG), the parent company of internet search engine Google and streaming platform YouTube.

Alphabet operates what might as well be a monopoly in internet search. According to GlobalStats, Google has consistently maintained global search engine market share of 91% to 93% for at least the past two years. Its next-closest competitor, Microsoft's Bing, hardly registered with a 2.29% share of the search engine market in April 2021. Being such a dominant force in search means advertisers will pay up for prime placement. It also suggests that the company's traffic acquisition costs should decline over time. As the U.S. and global economy improve, ad spending should really pick up. 

But Alphabet is about more than just internet search. Ad revenue generated from YouTube -- one of the three most-visited social sites on the planet -- jumped 49% in the first quarter to $6 billion. Meanwhile, revenue from cloud infrastructure segment Google Cloud rose 46% to $4 billion. These once small ancillary operations are now on track to contribute $40 billion in sales to Alphabet on an annual run-rate basis. 

Despite its $1.6 trillion price tag, Alphabet is still a bargain.

A person using a dropper to place liquid samples in test tubes.

Image source: Getty Images.

AstraZeneca

For two decades, pharmaceutical stock AstraZeneca (NASDAQ:AZN) was a largely forgettable drug developer that struggled with competition and the patent cliff. Today, it's reinvented itself into a bona fide growth stock with a bright future.

The primary growth driver for AstraZeneca is the company's oncology segment. In the first quarter alone, constant currency sales jumped 16% to $3.02 billion. The company's blockbuster trio of Tagrisso, Imfinzi, and Lynparza led the way with respective constant-currency sales growth of 13%, 17%, and 33%. Diabetes blockbuster drug Farxiga also deserves a mention with its 50% constant-currency sales growth in Q1 2021. The company's brand-name treatments are on fire, and it's led to sustainable double-digit topline growth. 

Equally exciting is AstraZeneca's pending acquisition of Alexion Pharmaceuticals (NASDAQ:ALXN). Alexion is a developer of ultra-rare therapeutics. Though it's risky developing treatments for such a small group of patients, success is usually met with no competition and little or no pushback from health insurers on high list prices.

The best part about the Alexion deal is the company developed a replacement for its top-selling drug, Soliris. The next-generation therapy, known as Ultomiris, is administered less frequently, which is a positive for patients. Eventually, Ultomiris will gobble up Soliris' sales and lock-up Alexion's/AstraZeneca's cash flow for a long time to come.

A young businesswoman holding a credit card in her left hand, with an open laptop in front of her.

Image source: Getty Images.

Mastercard

Another unbeatable stock that can deliver superior returns with Biden in the White House is payment facilitator Mastercard (NYSE:MA).

Like most financial stocks, Mastercard is cyclical. This means it struggles when the U.S. and global economy contract or enter a recession and it thrives when the economy is running on all cylinders. That's because it relies on merchant fees via payments to drive its top and bottom line. But the thing to understand about cyclical companies like Mastercard is that time is on their side. Whereas recessions often last for a few quarters, periods of expansion usually last many years. Considering how much money the Biden administration is attempting to pump into the U.S. economy, Mastercard should have a field day.

Something else to consider is that Mastercard has chosen not to be a lender. Although some of its peers do act as both processors and lenders (via credit cards), and are therefore able to double-dip during economic expansions, Mastercard's avoidance of lending is actually a smart move. When recessions inevitably strike and credit delinquencies rise, Mastercard doesn't have set aside cash. This is why it rebounds much quicker than its peers during the early stages of a recovery.

The math here is simple: As the economy picks up steam, consumers and businesses are going to spend, spend, and spend some more. That's music to the ears of all Mastercard shareholders.

Ascending stacks of coins placed in front of a two-story residential home.

Image source: Getty Images.

Annaly Capital Management

Don't worry, I haven't forgotten about you dividend income-seekers out there. If a Biden bull market takes shape, mortgage real estate investment trust (REIT) Annaly Capital Management (NYSE:NLY) could be a smart place to put your money to work.

Without getting overly technical, mortgage REITs like Annaly borrow money at short-term lending rates and use it to purchase securities with higher long-term yields. In Annaly's case, we're primarily talking about mortgage-backed securities (MBS). The difference between the long-term yield received and the short-term borrowing rate is known as net interest margin (NIM). The wider the NIM, the more profitable Annaly is, and the bigger the dividend payout it can provide to shareholders. Right now, Annaly Capital is yielding a jaw-dropping 9.7%.

What makes Annaly such a perfect stock to buy is that we're witnessing the yield curve steepen. When the U.S. economy is rebounding from a recession, it's normal for long-term yields to rise and for short-term yields to fall or flatten out. When this happens, Annaly usually experiences a widening of its NIM.

Additionally, Annaly almost exclusively buys agency securities. This is a fancy way of saying that the MBSs it's purchasing are backed by the federal government in the event of a default. This protection is what allows the company to utilize leverage to its advantage, thereby pumping up its profits.

A cat staring at a couple of uneven stacks of coins.

Image source: Getty Images.

Trupanion

Lastly, companion animal health insurance company Trupanion (NASDAQ:TRUP) has all the look of an unbeatable stock to buy in a Biden bull market.

The pet industry may not offer flashy growth prospects like cybersecurity or cannabis, but it's arguably the most consistent growth opportunity. It's been more than a quarter of a century since year-over-year U.S. pet expenditures declined. Further, the American Pet Products Association notes that the percentage of American household owning a pet has increased from 56% in 1988 to 67% by 2019-2020. If we've learned anything about pet owners, it's that they're willing to spend big bucks to ensure the well-being of their four-legged family members.

Trupanion, which recently lifted the hood on its first-quarter operating results, is closing in on 1 million total enrolled pets (943,854 at the end of Q1 2021). Amazingly, this only represents a little over 1% penetration of the U.S. market. In the U.K., about 1 in 4 pet owners purchases insurance for their cat or dog. If Trupanion can achieve a similar penetration rate, its addressable market would be more than $32 billion. 

This is a company that's spent two decades building up rapport with veterinarians and their staff at the clinical level. It's also the only major companion animal health insurance provider with software capable of handling payment to veterinarians at the time of checkout.

The sky is the limit for Trupanion.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.