Mann+Hummel is a leader in filtration. The family-owned German business is not a household name, but it has been providing component parts to the auto industry for more than 80 years. "For almost every part of a vehicle that requires filtration, we offer a product—air filters, oil filters, etc.," says Peter Kleine, senior manager for standards and risk management/corporate purchasing.

"Mann+Hummel is what you might call a 'hidden champion,'" he continues. "We are not widely known outside the automotive industry, but we have been very successful in the last decades, growing and staying profitable. We have a production footprint in every region of the world, with more than 20,000 employees and a turnover of almost 5 billion euros annually."

Not surprisingly for a global manufacturer, Mann+Hummel has an extensive international supply chain. "We buy raw-material–based products, like resin and chemicals, but we also buy parts like O-rings," Kleine says. "Our supplier base is heterogeneous. We have around 2,500 direct suppliers, which are very diverse in terms of size, turnover, and their market position. We do local and regional sourcing, but also make use of lower-cost manufacturing in Asia through global sourcing, especially for our production in Europe."