Those changes have kickstarted a small but fast-growing medical-marijuana industry, estimated to be worth about $1.7 billion as of 2011, according to See Change Strategy, an independent financial-analysis firm that specializes in new markets. In Colorado alone, sales topped $181 million in 2010, and the business employed 4,200 state-licensed workers, says Aaron Smith, executive director of the National Cannabis Industry Association , a nonprofit trade group that campaigns for marijuana’s federal legalization.

In addition to profiting itself from growing and selling marijuana, the industry benefits a slew of other businesses, such as insurers, lawyers and agricultural-equipment firms, experts say. “Call it the ‘green rush,’” says Derek Peterson, CEO of GrowOp Technology, an online retailer of hydroponics — products used in the cultivation of indoor plants — and a subsidiary of OTC stock Terra Tech TRTC +8.57% . “The industry is expanding, and there are all kinds of investment opportunities.”


Read more via How to invest in legalized marijuana – MarketWatch.