SAN FRANCISCO — Venture capitalists and entrepreneurs have been lobbying federal regulators to protect at least some virtual currencies from being categorized as securities, a designation that would carry significantly more oversight.

The venture capital firm Andreessen Horowitz helped assemble a group of investors and lawyers that met with the Securities and Exchange Commission in late March. They also proposed a “safe harbor” for some virtual currencies, according to a copy of the proposal reviewed by The New York Times and three people briefed on the effort who agreed to speak on the condition of anonymity because the proceedings were confidential.

Regulators have indicated in private meetings that they are considering whether virtual currencies — including Ether, the second most widely used digital token — should be categorized as a security, according to three people who have been in the meetings. That designation could cause a significant drop in the value of Ether.

“It’s a ‘come to the lord’ moment,” said Richard Levin, a lawyer at the firm Polsinelli who works with companies in the space. “We are seeing a watershed moment in which many firms in the digital asset community who may have been ignorant of the law — or poorly informed — are now coming to terms with the fact that they are subject to regulators.”