The May issue of SFO Stocks, Futures and Options Magazine has an interesting interview with Richard Sandor, Chairman and CEO of the Chicago Climate Exchange. He pioneered the creation of financial futures in the 1970s, including Ginnie Mae futures.
He states that "Financial inventions, like the limited liability corporation, were more important than the steam engine."

He also notes that commoditizing the market for home ownership undermined red lining against single women and minority groups. "You can get a mortgage in 24 hours--you hit the web, you get a certain rate and you close. I think the value of capital market inventions is often significantly underestimated."

Lynn Kiesling wrote an article about the economics of trading credits for greenhouse gases.

None of these innovations have been patented, unlike the steam engine.