A five-member panel of the U.S. Securities and Exchange Commission (SEC) has voted 4-1 in favor of a proposal that could make it more difficult for cryptocurrency companies to operate as custodians of digital assets in the future.

According to a Feb. 15 statement from SEC Chairman Gary Gensler, the proposal proposes that amendments to the 2009 custody rules apply to custodians of all assets, including crypto assets. The SEC has yet to formally approve the proposal.

Gensler said that currently, some cryptocurrency exchanges that offer custodial services are not really "qualified custodians."

According to the SEC, eligible custodians are generally federally or state chartered banks or savings associations, trust companies, registered brokers, registered futures commissioners, or foreign financial institutions.

In order to become a "qualified custodian" under the new proposed rules, U.S. and offshore companies would have an additional need to ensure that all custodial assets - including cryptocurrencies - are properly segregated, and those custodians would need to pass additional scrutiny, such as annual audits by public accountants, and other transparency measures.

However, not every SEC member is on board with Gensler's plan. While the proposal itself is not "enforcement regulation," Commissioner Hester Peirce said that "the SEC's latest announcement appears designed to take immediate effect" to crack down on the cryptocurrency industry.

As for the proposal itself, Peirce thinks it will do more harm than good. Such stringent measures would force investors to move their assets out of entities that already have adequate safeguards procedures in place to mitigate and prevent fraud and theft, she said.