Robinhood has attracted a generation of young investors, and it's easy to see why. Its platform features a colorful user interface, support for cryptocurrency, and a wealth of educational material for beginners.

Given their age, media outlets often portray Robinhood traders as naïve. But some of the trendiest stocks on the platform could actually be smart long-term investments. For instance, Airbnb (ABNB 4.03%) and Square (SQ 5.41%) currently rank among the most widely held stocks on Robinhood.

What's more, millionaire money managers like Larry Fink and Cathie Wood are also snapping up shares of these disruptive companies. Here's what investors should know.

Luxury lodgings, featuring a wood-themed room with a view of the ocean.

Image source: Airbnb

Airbnb

During the first quarter, Larry Fink's BlackRock added 1.2 million shares of Airbnb, bringing its total to 2.8 million. While this position is less than 1% of its portfolio, the decision to buy is still meaningful, especially given the state of the travel industry. But this move actually makes sense.

Airbnb's platform connects potential guests with 4 million hosts -- both individuals and professional property managers -- in over 100,000 cities. This helps hosts monetize spare rooms, vacation homes, and even treehouses, while allowing travelers to find lodgings and experiences around the world.

Airbnb's unique business model has disrupted the industry. In fact, with a market cap of $93 billion, it's worth more than Hilton, Marriot, and Hyatt combined. Prior to the pandemic, the company was also growing much faster than these rivals.

Revenue ($billions)

2017

2019

Change

Airbnb

$2.6

$3.7

42%

Hilton

$8.1

$9.5

16%

Hyatt

$4.5

$5.0

13%

Marriott

$20.5

$21.0

3%

Data source: Airbnb, Hilton, Marriott, and Hyatt SEC filings.

In 2020, Airbnb's revenue fell 30% -- but even so, its business still proved more resilient than big hotel chains. Hilton, Hyatt, and Marriott saw sales plummeted 54%, 59%, and 50%, respectively, last year.

Moreover, the future is starting to look a little brighter. In the first quarter of 2021 Airbnb reported revenue of $887 million, up 5% from the prior year. But the standout figure was gross bookings value. This metric surged 52% to $10.3 billion, implying strong demand in the coming quarters.

As a final thought, Airbnb's ability to help guests book unique spaces is a significant advantage. Travelers can stay at a vacation home along the beach, a rustic villa in a rural locale, or a flat in the heart of a big city -- no hotel chain can offer that type of privacy or immersive experience. That's why I'm not surprised to see BlackRock buying this stock.

Square

During the first quarter, Cathie Wood's Ark Invest bought 3.9 million shares of Square, bringing its total position to 11 million shares. Square is now Ark's third-largest holding, representing nearly 5% of its portfolio.

Person using smartphone to make a payment at a Square register.

Image source: Square

Chances are you've seen Square hardware -- the sleek tablets and chip readers often used by small businesses -- but that only scratches the surface. Square's platform is an end-to-end commerce solution for sellers of all sizes, addressing everything from payment processing and inventory management to payroll and financing.

In the first quarter Square continued to build its ecosystem with the launch of Square Messages. This service allows sellers to chat directly with buyers, helping them create lasting relationships.

Notably, Square's persistent innovation is bringing larger businesses to its platform too. Gross payment volume (GPV) from mid-market merchants jumped 43% in Q1, growing more than twice as fast as total GPV. Mid-market merchants (i.e. those with annualized sales above $500,000) now represent 30% of Square's total GPV, up from 24% in 2019.

But the real story in Q1 was Cash App: Gross profit surged 171% to $495 million, driven by strong consumer engagement with Square Cash Card and bitcoin. Moreover, a new integration with Square Loyalty -- a product that helps sellers launch rewards programs -- should continue to drive Cash App engagement in the coming quarters, while giving sellers another tool to build rapport with buyers.

Despite significant headwinds created by the pandemic, Square has managed to grow at a stellar pace in recent years.

Metric

2017

Q1 2021 (TTM)

CAGR

Gross Profit

$839.3 million

$3.2 billion

50%

Data source: Square SEC filings. CAGR = compound annual growth rate.

Payment processing is a highly fragmented industry, but Square's end-to-end ecosystem removes much of that complexity, helping sellers manage their business across physical and digital locations.

Cathie Wood tends to focus on innovative and disruptive technologies, and Square certainly fits that description. That's why I'm not surprised to see Ark buying this fintech stock.