When investors think of well-known companies, they tend to focus on the company's best-known brands. However, companies often generate more money from products or businesses that you've never heard of. For example, Johnson & Johnson (JNJ 0.52%), CVS Health (CVS 1.10%), and 3D Systems (DDD -1.73%) make more money serving their lesser-known markets than they do by serving the markets that they're better known for.

Source; Johnson & Johnson.

More than a household name
You're probably familiar with Johnson & Johnson's Band-Aid, Listerine, and Tylenol brands, but Johnson & Johnson's pharmaceuticals business produces more than twice the $3.5 billion in quarterly revenue that its consumer-goods business does.

Sales from the company's drug business totaled $7.9 billion in the second quarter alone, and that success is due in large part to fast-growing sales of Xarelto, an anticoagulant, Imbruvica, a leukemia and lymphoma therapy, and Invokana, a diabetes drug.

Xarelto continues to win prescription market share away from warfarin, and as a result, its sales increased 30.7% from a year ago to $472 million in the second quarter. Imbruvica's expanding label led its revenue to grow to $154 million last quarter from $42 million a year ago, and Invokana, which reduces blood glucose by reducing how much of it is reabsorbed by the kidneys, posted Q2 sales of $318 million in the quarter, up from $117 million a year ago.

Xarelto, Zytiga, and Invokana are growing quickly, but each is battling for market share against drugs that work similarly. For that reason, their potential to move the needle makes J&J's drug business far more important to investors than J&J's more recognizable consumer-goods brands.

Source: CVS Health

A $100 billion business you've never heard of
CVS Health's pharmacies are neighborhood staples, but it's CVS Health's massive pharmacy benefit manager, or PBM, business that generates the majority of the company's revenue.

In the second quarter, CVS Health's PBM sales totaled a whopping $24.4 billion, accounting for nearly 66% of CVS Health's overall sales and putting the business on pace to post nearly $100 billion in total sales this year.

The success of CVS Health's PBM business stems from an ever-growing need for healthcare payers, such as insurers and employers, to rein in sky-high healthcare costs. CVS Health's PBM does so by helping health payers negotiate lower drug costs with manufacturers and increasing patient adherence to medicines, which can reduce costly hospitalizations.

Even though CVS Health's PBM business captures just a small sliver of the money changing hands between payers and drugmakers, the sheer magnitude of revenue generated by its PBM business means that its impact on CVS Health's bottom line still amounts to billions of dollars annually.

With drug prices continuing to increase and drug demand expected to climb because of an increasingly older population, it's unlikely that CVS Health's PBM business will wane anytime soon, and that makes it the business that investors ought to be paying attention to.

Source: 3D Systems.

Forget consumers: This market is the real story
Media attention may have people thinking they'll have their own Star Trek replicator in their home soon, but it's the healthcare sector's use of 3D printing that's more important to 3D Systems' business than the consumer.

Last year, acquisitions and organic growth led 3D Systems' healthcare revenue to grow 80% year over year to $129 million, or 22.8% of sales. That figure dwarfed sales to consumers, which were up 26% to $43.8 million and represented just 6.7% of sales in 2014.

Healthcare's outsize impact on 3D Systems has continued in 2015, as demand and additional acquisitions have boosted healthcare sales by 31.7% to $64.8 million through the first six months of 2015. For comparison, consumer revenue totals $25.3 million during the first six months.

Why has healthcare become such an early adopter of 3D printing? Because 3D printing allows the industry to do things it otherwise couldn't. For example, surgeons can print exact copies of a damaged organ to better understand and plan their surgery, and 3D simulators can allow them to practice complex procedures ahead of time. In addition, 3D printers can be used to sculpt custom implants that fit precisely where knees, hips, or other appendages are needed, and dentists can create perfect dental implants to replace damaged or missing teeth.

Because demographics support rising healthcare demand over the coming decade, it's likely that healthcare will remain the key driver of 3D Systems' growth for the foreseeable future, making it, rather than the consumer, the opportunity investors should focus on.

Tying it together
Experts often remind investors to invest in what they know, but sometimes companies operate businesses or sell into markets that stretch far beyond what you may think. In the case of Johnson & Johnson, CVS Health, and 3D Systems, the reason shares may move higher or lower in the future may be less tied to what they're better known for and more to other businesses, and that fact serves as a great reminder of why it pays to do some research so that you better understand a company before buying its shares.