Not long ago, $1 trillion seemed like a near-impossible milestone for a publicly traded company.

As recently as 2018, there were no American companies worth $1 trillion. Today, there are five -- AppleMicrosoftAmazonAlphabet, and Tesla -- with the iPhone-maker leading the pack at a market cap of $2.8 trillion. Not long ago, there was a sixth trillion-dollar company, but Facebook-parent Meta Platforms' recent collapse has shaved its market value down to less than $600 billion.

There's no doubt that there will be more $1 trillion companies in the future, and some like Warren Buffett's Berkshire Hathaway are already knocking on the door. Keep reading to see why Airbnb (ABNB 0.91%) and Paypal (PYPL 0.75%) could also hit the 13-digit mark by the end of the decade.

An arrow going up made of $100 bills

Image source: Getty Images.

1. Airbnb

Airbnb has disrupted the travel industry, making everyone's home into a potential hotel. The concept might have once seemed edgy, but it's gone mainstream in only a few years. 

While Airbnb has competitors that also offer home-sharing like VRBO, the company's brand is synonymous with the business, and it's also different from many of its competitors because its accommodations are largely from individual hosts rather than professional short-term rental companies.

In order to reach a $1 trillion market cap, a company needs a large addressable market, and there's no question Airbnb has that. In its prospectus ahead of its IPO, the company estimated a $3.4 trillion addressable market between accommodations and experiences. Airbnb isn't going to kill the hotel industry, but market share in lodging is shifting steadily from traditional to apartments and home-sharing accommodations. The pandemic also added to Airbnb's advantage over hotels, as it can offer places to stay anywhere in the world, while traditional hotels tend to be clustered in downtowns, tourist areas, and airports, all of which have struggled over the last two years. Meanwhile, the rise of remote work should help fuel Airbnb's growth as well.

Airbnb is currently trading at a lofty valuation, but the company could grow its revenue by 20% annually over the next decade. That would give it $37 billion in revenue in a decade. That alone won't be enough to get the company to a $1 trillion valuation, but its margins are also ramping up quickly as its business model is scalable. Airbnb's EBITDA margin in 2021 was 26.7%. If that improves to 40% in ten years, the company would have $15 billion in EBITDA, meaning a $1 trillion valuation would price it at 67 times EBITDA. That's well within the company's reach if it executes on its vision for transforming the travel industry. Currently, Airbnb is worth roughly $100 billion.

2. Paypal

Paypal (PYPL 0.75%) pioneered online payments, and remains the leader of the industry. The company currently has a market cap of slightly more than $100 billion, but Paypal stock has fallen sharply in recent months amid the broader sell-off in growth stocks, down more than two thirds from its peak last summer.

Indeed, the company's growth rate is taking a breather after a pandemic-driven boom, but Paypal's long-term growth still makes it appealing. The company is forecasting 15%-17% revenue growth this year, or 19%-21% excluding EBay, which said last year it would stop using Paypal to pay its sellers.

Despite the loss of EBay, Paypal still has a number of tailwinds in its favor, including the growth of e-commerce, the movement of payments to digital channels, recent acquisitions like Venmo, and expanding its customer base. It recently became a payment option on DoorDash, for example, through both Paypal and Venmo, and is now used by DoorDash for some of its direct credit card processing.

The best reason though to bet on Paypal right now may be its valuation. Based on its adjusted earnings per share of $4.60 last year, the stock is trading at a price-to-earnings ratio of 21.7, which is cheaper than the S&P 500's P/E multiple at 22.2. With 20% annual EPS growth over the next decade and modest multiple expansion, Paypal could hit the $1 trillion mark in the by 2030.