United Rentals is the largest equipment rental company in the world. It owns a fleet of cranes, aerial lifts, generators, trench safety gear, surface protection mats, and dozens of other equipment types, all available to rent by the hour, day, week, or month. Construction companies, factories, energy firms, and municipalities pay to use the equipment temporarily rather than buy it outright. That single idea, rent instead of own, drives 86 percent of the company's $16.1 billion in annual revenue. The diagram below traces where the money goes.
Five years of financial data tell a clear story of growth. Revenue climbed from $9.7 billion in 2021 to $16.1 billion in 2025. Operating cash flow rose from $3.7 billion to $5.2 billion over the same period. The business generates a lot of cash from its rental transactions, and that cash funds new equipment purchases, acquisitions, dividends, and share repurchases.
Gross margin has been less consistent. It rose from 39.7 percent in 2021 to 42.9 percent in 2022, then slipped back each year after that, reaching 38.2 percent in 2025. The company's own explanation points to a growing share of specialty revenue that carries lower margins than core equipment rentals, plus inflationary cost pressures on repairs, labor, and fuel. Revenue keeps climbing, but each dollar of revenue is leaving slightly less gross profit behind than it did three years ago.
The debt load is the other number worth watching carefully. Net debt has grown from $9.5 billion in 2021 to $13.8 billion in 2025. Total debt as of December 31, 2025 stood at $14.2 billion, with $4.1 billion of that carrying variable interest rates. Interest rates on the company's debt instruments have risen significantly in recent years. The weighted average variable rate was 1.4 percent in 2021 and 5.4 percent in 2025. The company does generate enough operating cash to service this debt, but the size of the obligation means that any drop in revenue or rise in rates lands harder than it would for a less leveraged business.
United Rentals has grown heavily through acquisitions, including the Ahern Rentals purchase in December 2022 and the Yak acquisition in March 2024. That acquisition history has left $7.1 billion in goodwill sitting on the balance sheet. The company's most recent goodwill test showed that all reporting units had fair values exceeding their carrying amounts, but by a smaller cushion than the year before. In 2024 the cushion was at least 60 percent. By 2025 it had narrowed to at least 32 percent. That narrowing is not a crisis, but it is a direction worth noting.
The specialty segment is now a major part of the business. It represented 31.7 percent of revenues in 2025, compared with just 7.3 percent in 2013. Specialty includes trench safety equipment, portable generators, fluid containment systems, mobile storage, and surface protection mats. Adding Yak in 2024 pushed surface protection mats from 2 percent to 4 percent of equipment rental revenue in a single year. Specialty growth is a deliberate strategy, but it comes with complications.
Industrial customers, including energy companies, account for approximately 48 percent of rental revenue. That concentration creates a direct link between oil and natural gas prices and United Rentals' top line. When energy companies cut exploration and production spending, they rent less equipment. The company has no control over commodity prices, and a sustained drop in oil and gas activity would remove nearly half its revenue base from the strongest part of its demand picture.
Equipment supply is another documented pressure. The company depends on a relatively concentrated group of suppliers. The top ten suppliers accounted for 52 percent of capital expenditures in 2025. New equipment costs have risen due to raw material prices and tariffs, and the company has said those cost increases could continue. If suppliers face financial difficulty or raise prices further, maintaining and growing the fleet becomes more expensive than the current plan assumes.