The SEC has done “bits and pieces,” but is now “laying the groundwork for a bigger review”, a person briefed on the matter told the Financial Times. “ETFs are growing like bunnies. It’s a great success story, but as a forward-looking regulator the SEC has to be on top of any potential issues that may arise in the future.”

The ETF industry’s impact on financial markets may continue to grow as investors increasingly turn to the investment vehicle to gain market exposure. For instance, the underperformance and high fees of traditional mutual funds have accelerated the shift toward passive index-based funds, like ETFs.

SEE MORE: SEC Scrutinizes ETF Industry, Mulls New Rules

Earlier this year, SEC chair Mary Jo White highlighted the ETF industry’s “astounding” growth and hinted the regulator was considering an examination of the potential implications. “The SEC has taken a number of initial actions to share our thinking on these issues, and further regulatory steps beyond additional disclosures may be needed to address some of these issues,” Jo said in May.

For more information on the ETF industry, visit our current affairs category.