Battle of the billionaires erupts over Keystone

Hedge funds speak up on Keystone XL

Billionaire investors love fighting with each other over the markets, safely out of public view in sleek Greenwich or Manhattan offices. But a new political fight is pushing them into a high-profile debate over the future of energy consumption in the U.S.—and they are literally taking to the streets of Washington to make their views heard.

The brawl is over an upcoming decision by the Obama administration about whether energy company TransCanada should be allowed to build a massive oil pipeline, called Keystone XL, that will ship oil sands in Northern Canada to refineries in the Gulf of Mexico. The State Department—in charge because the project would cross an international border—is still studying the issue and its environmental impact. A decision could come next year.

The two sides couldn't be more convinced of their positions. Former Vice President Al Gore recently called the controversial project an "atrocity." House Speaker John Boehner has said President Barack Obama should "stand up for middle-class jobs and energy security and approve the Keystone pipeline."

Likewise, prominent investors have planted themselves on opposite sides of the issue.