Donaldson Company, Inc. is a vertically integrated filtration company engaged in the production and marketing of air filters used in a variety of industry sectors, including commercial/industrial, aerospace, chemical, alternative energy and pharmaceuticals. Also the company's research division, located in Minneapolis, Minn., participated in defense-related projects for various military applications. As a multinational company it operates in Belgium, Mexico, China, UK, Czech Republic, Malaysia, Thailand, USA, South Africa, Russia, Japan, Italy, Germany and France. In fiscal year 2016 20.3% of sales came from business in the Asia-Pacific region, 28.5% from Europe and 42.2% from the US. The company also makes aftermarket parts. There was significant growth in the size of the company in terms of market value in 2009, going from about $2 billion at the start of the year to $3.26 billion in May 2010. Although sales were steady between 2007 and 2010 long term debt rose 98.6% over that period; Long term debt increased 44% in 2008 and remained near that level until January 2011 when it fell 17% quarter to quarter. No single customer contributes more than 10% of revenue. Wikipedia