BlackRock is calling for a new rule in the $3 trillion exchange-traded funds market that would remove some of the impediments faced by wannabe issuers and potentially curtail the advantages of early movers—like BlackRock, according to Mark Wiedman, global head of the company’s iShares business. “There should be a single rule that governs plain-vanilla ETFs in the United States,” Wiedman said during an interview. “There’s an unlevel playing field.” Read the original story from Bloomberg.