The European company that is buying Panera Bread may not be a household name, but its brands are.

JAB Holding, a privately held company and investment arm of the wealthy Reimann family, owns well-known brands such as Keurig Green Mountain, Krispy Kreme Doughnuts, Coty and Jimmy Choo. On Wednesday, the company, which has been steadily building a coffee and breakfast empire over the last five years, said it would add Panera Bread to that list in a $7.5 billion acquisition.

The German billionaires who own JAB are notoriously media-shy, and control a fortune that dates back centuries to the founding of the Benckiser chemical company. Today, JAB's holdings range from beauty products to food and luxury goods.

The family isn't active in the day-to-day running of the company, instead it is overseen by three senior partners — Peter Harf, Bart Becht and Olivier Goudet — and eight others who focus on business development, finance, legal, tax and human resources.

JAB began building its position in coffee and breakfast in 2012 when it took a stake in D.E. Master Blenders. At the time, the company had no plans to purchase the Amsterdam-based coffee company, it told Bloomberg then.

But later that year, it bought Peet's Coffee & Tea for $974 million and Minnesota-based Caribou Coffee for $340 million. In the years that followed, JAB would go on to spend billions expanding its coffee empire.

Eventually in 2013, JAB agreed to pay $9.8 billion to purchase D.E. Master Blenders. That company became Jacobs Douwe Egberts when JAB merged it with the coffee division of Mondelez International in 2015, which it bought for around $4 billion.

JAB in 2014 scooped up Einstein Bagels' parent company, Espresso House and Baresso Coffee.

In 2015, JAB purchased Keurig Green Mountain for $14 billion and coffee roaster and retailer Stumptown Coffee and coffee bar chain Intelligentsia coffee. The next year, Krispy Kreme was added to the portfolio.

JAB's coffee expertise may be just what Panera needs at this stage in its development. In turn, Panera has a few things it could teach JAB, including how to leverage mobile ordering.

"An acquisition of Panera Bread not only brings them a digital platform that ultimately that they can use across their portfolio, but also it provides them an opportunity for some vertical integration of the coffee business," Bob Derrington, senior research analyst at Telsey Advisory Group, said in an interview Tuesday with CNBC's "Power Lunch."

Last year, JAB was in the process of developing Coffee & Bagels, a new type of coffee chain that paired Caribou Coffee and Einstein Bros. Bagels, two of JAB's brands.

Panera's coffee products have long been seen as a weak competitor against coffee giants like Starbucks, however, JAB's acquisition could change that.

The coffee market has become more saturated in recent years, with chains like Dunkin' Donuts and McDonald's stepping up their caffeine game by launching cold brew and other, more upscale coffee beverages.

Through its parent, Panera will have access to more than half a dozen partner brands that specialize in coffee.

"To the degree we can use any resources and capabilities of our partner brands within JAB to do a better job, you can count on us to take advantage," Panera CEO Ron Shaich said on CNBC's "Squawk on the Street" Wednesday.

The 63-year-old Shaich said he plans to stay on as Panera's chief executive, and added, JAB is "a wonderful partner for Panera."

"They're long-term investors," he said. "They measure their investments in centuries, not decades. They are committed to our strategy. They're committed to our company franchise model. They're committed to our team."

Watch: Panera CEO says JAB shares company's values