Market Extra: Big question with dollar under fire from rival countries and currencies: What happens to markets if the greenback loses its dominance?

Is “King Dollar” in danger of losing its crown?

Probably not yet, but the rapid unwinding of last year’s torrid rally in the U.S. dollar, combined with efforts in Beijing and beyond to ease dependence on the buck, have helped to reinvigorate speculation that the greenback’s dominance over international trade and finance may be moving toward its twilight.

Talk…