As exchange-traded funds grow in popularity, regulators appear to be recognizing the need for targeted oversight of the industry. Recent technological glitches also are highlighting the risks surrounding ETF trading and the possible impact on the wider financial markets. A white paper released by BlackRock gave an overview of ETF primary trading and BlackRock’s recommendations in areas “where policy makers, regulators, and the industry can act to strengthen the ecosystem around ETFs, decrease operational risk, and reduce frictions.” According to a Wall Street Journal report citing data from research firm XTF, there are now more than 1,800 exchange-traded funds and their holdings are valued at $2.7 trillion. The WSJ story notes that the SEC has never written rules specifically for ETFs, leaving them to operate on the guidance provided by SEC exemptive orders and rules applicable to mutual funds. The SEC recently approved rule changes proposed by Bats BZX Exchange, Inc. to add specific continued listing standards for exchange-traded products and to specify delisting procedures for these products, requiring ETFs to meet standards detailed in 314 pages of exchange filings unless they are granted an exception. According to a Reuters report, the recent ETF regulatory actions highlight concerns over the potential for trading abuses, especially for ETFs that track indexes which include assets that are not traded often. Some industry participants have criticized the latest regulatory action in comments filed with the SEC. The SEC also recently rejected an application to list an ETF that would track the digital currency known as Bitcoin.