China's moves to set up trading oil in yuan have sparked enthusiasm about what could be a shift in the global financial system: a reduced role for the U.S. dollar. Players like Adam Levinson, founder of hedge fund Graticule Asset Management Asia, call it a “huge story” to come.

But with policy makers prioritizing market stability over internationalization, plans laid back in 2012 to begin oil-futures trading priced in yuan or dollars in Shanghai that year are still pending. The latest from the city's International Energy Exchange: It's coming soon, with test trades scheduled this weekend.

“This contract has the potential to greatly help China's push for yuan internationalization,” said Yao Wei, chief China economist at Societe Generale SA in Paris. “But its success will hinge critically on the degree of freedom allowed for the capital flows related to the contract.”