Founded in 1972, Kleiner Perkins Caufield & Byers is one of the oldest firms on our list. The Silicon Valley, CA-based company has invested heavily in greentech and IT. But as the first to form a practice dedicated to life science investments, KPCB has remained commited to investing in the fields of biopharma, medical device, diagnostics and personalized medicine. According to its website, the venture capital firm prefers to invest in early-stage companies. After forming a $360 million fund in 2007, the company expanded its team into China and began investing more in China-based ventures. Now investing its 13th fund, KPCB has awarded capital to more than 450 companies over the past 37 years.