The United States Securities and Exchange Commission (SEC) has delayed a rule change to the Securities Act, which would allow Bitcoin (BTC) exchange-traded funds (ETF) list, according to its press release on March 29.

ETFs are securities tracking a basket of assets proportionately represented in the fund’s shares, also considered as a potential step forward for the mass adoption of cryptocurrencies.

On February 15, Bitwise filed the application with NYSE Arca to reach a decision in 45 days and can be extended the review period to 90 days.

NYSE Arca and Bitwise filed the permission in 2018 and planned to launch Bitcoin-related ETFs in January. The firms planned to launch five separate ETFs linked to both bull and bear futures contracts on NYSE Arca.

The SEC also put back the decision on VanEck/CBOE Bitcoin ETF with the same conditions, which means the new deadline is on May 21.

In last January, the CBOE filed the application requesting for a rule change when the U.S. government shutdown decreased the SEC’s operational capacities. CBOE and VanEck registered with SEC on January 31 after the government shutdown was resolved.

The application was delayed since the commission postponed its decision. The first firm was done on June 6, 2018. In last August, the SEC delayed the decision until Sep.30, then claimed that the agency has not “reached any conclusions with respect to any of the issues” on the rule change.

The Bitcoin ETF possibility has some concerns by some industry experts. In last January, Brian Kelly, crypto entrepreneur and CNBC contributor, Kelly said that there is “no shot” for a Bitcoin ETF approval in 2019.