Some of the biggest companies in the U.S. are largely unknown to the public. While the following products or services pervade daily life, the corporate entities behind them are not well known, at least outside the investor community.

Here are three names that you have almost certainly used in the past day or two. 

Bull and bear on a financial newspaper

Image source: Getty Images.

Mobile data usage still has room to grow

If you used your cellphone today, you probably connected via a signal from American Tower (NYSE:AMT). American Tower is one of the largest real estate investment trusts (REITs) in the world that leases out cell towers to carriers, and it has benefitted from increased mobile data usage. 

The average U.S. smartphone user consumed about 9 gigabytes per month in 2019, up 450% from five years ago. The company quoted an industry study on its earnings conference call that forecast that same user will consume 45 gigabytes per month five years from now, as 5G usage increases. American Tower generally has longer-term leases with its tenants, which include automatic pricing escalators.

The stock is trading at 34 times 2019 funds from operations (FFO) per share, so it is on the pricier side, at least for an REIT. The company trades at a 1.7% dividend yield, so at least there is some income for investors. 5G stocks are hot at the moment, and American Tower is up 16% year to date. 

Connecting banks and merchants

If you used a credit or debit card recently, you may well have been a user of Fidelity National Information Services (NYSE:FIS) technology, which acts as the financial plumbing for banks and merchants. Fidelity's systems allow merchants to accept electronic payments, either at the point of sale (like a store) or online.

The company purchased Worldpay in 2019, and recently rolled out Open Banking Hub, which allows instant payments from a customer's bank account without needing to share account details with a third party. Essentially, the Open Banking Hub routes the customer to the bank's online app to complete the order. The customer can also check the account balance as well, which is an added benefit.

Fidelity National Information Services held up better in the March–April timeframe than most of the other financial stocks and is flat year to date. The stock is trading at 25 times expected 2020 earnings and has a 1% dividend yield. 

A historic name that has changed its focus

If you enjoyed a can of beer over the weekend, or perhaps used some aerosol product in an aluminum can, the container was probably made by Ball Corp (NYSE:BLL). The company has been around about 140 years, and was best known for the Ball mason jars that people used to preserve fruits and vegetables before refrigerators were common. Ball is no longer in the mason jar business, having sold those operations in the 1990s. It now focuses on aluminum cans and aerospace.

Aluminum beverage containers drive the business for the most part. The company is launching "infinitely recyclable" aluminum cups to replace plastic and paper, in response to consumer demand for a more sustainable solution. Ball is trading at 26 times expected 2020 earnings and is up 11% so far year to date. 

Sometimes the biggest names are largely invisible to the consumer. These companies operate in the background, they generally don't advertise on TV, and they don't have brand recognition. That said, you have probably used their products and services over the past day or two.