Some states require natural-gas companies use technology to capture gas during the construction and drilling of wells.

WSJ: Rise in U.S. Gas Production Fuels Unexpected Plunge in Emissions

The firm uses a foundation- and endowment-like approach to portfolio construction, investing primarily in early-stage technology companies, with some allocation to life sciences as well as early and growth investments in India and China.

FORBES: Midas List 2013: The Methodology