4 Top Stocks Long-Term Investors Should Buy in March

March 2026 is giving long-term investors something rare: legitimate market and company pullbacks despite some accelerating fundamentals. That suggests opportunities to grab onto.

These four companies aren't speculative bets. Each one generates real revenue, grows at double-digit rates, and dominates a market that is part of everyday life and not going away. Let's find out why they might be good investments in March.

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1. Axon Enterprise

Axon (NASDAQ: AXON) makes TASERs, body cameras, multiple other law enforcement-related products, and the software that ties them together. But describing it that way misses the transformation. Axon has become an artificial intelligence (AI)-powered public safety platform.

Fourth-quarter 2025 revenue hit $797 million, up 39% year over year. Full-year revenue reached $2.8 billion, marking the fourth consecutive year of growth above 30%. Annual recurring revenue surpassed $1.3 billion, growing 35%. Total future contracted bookings stood at $14.4 billion, up 43%.​

The company just set a 2028 target of $6 billion in annual revenue with 28% adjusted earnings before interest, taxes, depreciation, and amortization (EBITDA) margins. That's more than doubling the business in three years. The roadmap includes Axon 911 (built on acquisitions of Prepared and Carbyne), Axon Vehicle Intelligence, and Axon Assistant -- an AI tool that automates police report writing.

The valuation is rich, but the execution is richer. This is a long-term hold.

2. Vertiv

If you operate data centers running AI models, you very likely also need power and cooling to keep them running. Vertiv (NYSE: VRT) supplies both to data centers worldwide, and the demand curve is vertical.

Full-year 2025 revenue reached $10.2 billion, up 28% year over year. Adjusted operating margins expanded to 20.4%. Organic orders surged 81%, and the company exited 2025 with a backlog of $15.0 billion -- more than a full year of revenue. Adjusted free cash flow hit $1.89 billion, up 66%. Q4 earnings jumped 37% to $1.36 per share.

In late February 2026, Vertiv launched its OneCore integrated modular solutions and a Digital Twin platform designed for high-density AI data centers, backed by a partnership with Hut 8. The company also raised $2.1 billion through bond offerings to fund expansion. Management targets 22% to 24% operating margins over the medium term.

The AI infrastructure build-out isn't slowing down, and Vertiv is one of the few companies that physically can't be replaced by software. The stock's metrics look good too, for a safe, long-term hold.

3. TransMedics Group

TransMedics Group (NASDAQ: TMDX) operates the Organ Care System (OCS), a technology that keeps donor organs warm and functioning during transport -- replacing the decades-old method of putting them on ice in a cooler. The company also runs its own aviation fleet for organ transport through its National OCS Program.​

Full-year 2025 revenue hit $605.5 million, up 37%. OCS Liver now accounts for 36% of all U.S. liver transplant procedures. The company performed 5,139 U.S. OCS transplants in 2025, up from 3,735 in 2024. It manages the logistics of this with its fleet of 22 aircraft.

Operating profit reached $21.3 million in Q4, representing 13.2% of revenue. Net income for the year was $190.3 million. TransMedics guided for 2026 revenue of $727 million to $757 million, representing 20% to 25% growth. The company holds FDA approvals for heart and lung trials and is expanding into Italy and other European markets.

This is a company building a monopoly in organ logistics -- a market with zero viable competitors and a moral imperative driving adoption.

4. Fair Isaac

Fair Isaac (NYSE: FICO) is the credit score company of all credit score companies. I hear its name in commercials, on the radio, and coming out of every salesman's mouth. The vast majority of mortgage, auto loan, and credit card decisions in America are made with the help of a FICO score. It has pricing power that borders on the obscene.

Fiscal year 2025 revenue was $1.99 billion, up 15.9%. Net income hit $651.9 million with a 32.8% net profit margin. Q4 revenue was $512 million with a 45.7% operating margin. Earnings per share (EPS) have grown at an average annual rate of 22.2% over the past decade.

The current catalyst is FICO Score 10T, a more predictive scoring model that incorporates trended credit data. I was a bit skeptical at first, but its adoption in the conforming mortgage market will drive incremental licensing revenue for years.

FICO also runs a growing software analytics business that expands its addressable market beyond credit scoring. The stock has pulled back around 25% year to date, creating a rare entry point for a near monopoly with expanding margins.

The company also announced a $1.5 billion stock buyback earlier this month. It's a strong buy with solid financials.

Micah Zimmerman has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Axon Enterprise, TransMedics Group, and Vertiv. The Motley Fool recommends Fair Isaac. The Motley Fool has a disclosure policy.