Manoj Bhargava, the reclusive founder and CEO of 5-hour Energy, occupies one of the more unusual positions in American business: he is almost certainly one of the wealthiest people in the United States, worth an estimated $4 billion or more, and almost nobody knows who he is.

Bhargava was born in Lucknow, India, and came to the United States as a teenager. After attending Princeton University for a year, he left without a degree and spent 12 years living in ashrams in India before returning to the United States and embarking on a series of business ventures. None of them was particularly successful until, in 2004, he launched a tiny 2-ounce bottle of energy supplement that would become one of the most successful consumer products in modern retail history.

5-hour Energy's rise was built on a deceptively simple insight: most people don't want to drink a large can of energy drink — they want a quick, efficient dose of alertness without the liquid volume. The product's small size made it perfect for placement at checkout counters, and Bhargava pursued an aggressive retail distribution strategy that eventually put 5-hour Energy in convenience stores, pharmacies, and grocery chains across the country.

Despite building a company that controls roughly 90 percent of the energy shot market and generates estimated annual revenues of more than $1 billion, Bhargava is legendarily press-averse and lives modestly relative to his net worth.

He has pledged to give 99 percent of his wealth to charity, with a particular focus on inventions and technologies that could improve living standards for people in the developing world. His private foundation has funded research into cheap water filtration, bicycle-powered electricity generation, and other practical technologies designed for communities without reliable infrastructure.

Bhargava's story is, in many ways, an archetypal American immigrant success narrative — and an unusual one.