Shares of Waste Management (WM 5.42%) surged on Thursday and were up 5.6% at their highest point in trading during the day through 1:30 p.m. ET.

With earnings season in full swing, you may have already guessed why the waste management stock rallied today -- it delivered solid numbers for its fourth quarter and full year. What's important to know, though, is why Waste Management's latest numbers should encourage you to buy the stock now.

Solid numbers from a solid waste leader

Here are some important numbers from Waste Management's Q4 and 2024 earnings report (all changes year over year):

• Revenue: Up 13% in Q4 and 8% in 2024
• Net income: Up 21% in Q4 and 19% in the full year
• Free cash flow (FCF): Up 22% in 2024

Therefore, 2024 was a solid year for Waste Management, as the company continued to expand its portfolio with acquisitions. After closing $800 million worth of acquisitions in the first nine months of 2024, Waste Management acquired Stericycle for $7.2 billion in November last year.

Stericycle is the largest medical waste management company in North America, and its acquisition expanded Waste Management's footprint into a new, high-potential end market. After the acquisition, Waste Management started reporting numbers for two segments: WM legacy business and WM healthcare solutions.

Waste Management also increased its dividend by 10% in December, with payment expected in March this year. This is the company's 22nd straight annual dividend raise.

Why Waste Management stock is a solid buy

Waste Management foresees another strong year ahead. It is projecting nearly 16% revenue growth at the midpoint in 2025, the bulk of it from acquisitions. The company expects strong growth in margins from both its segments and expects to grow its FCF by nearly 18% at the midpoint of its guidance range.

Importantly, Waste Management now expects synergies worth $250 million by 2027 from the Stericycle acquisition. That's double its original estimate.

The nature of Waste Management's business already makes it a resilient stock to own at all times. So, if you anticipate economic uncertainty in the not-too-distant future, there's no better time than now to buy and hold Waste Management stock, especially after its strong outlook for 2025.