SAN FRANCISCO — The Securities and Exchange Commission has sent subpoenas to dozens of people and companies behind the rise of so-called initial coin offerings, a clear sign of the agency’s desire to rein in the popular new fund-raising method.

Over the last few months, the commission has asked for information from companies that have sold new virtual currencies to raise money for their projects, as well as advisory firms and lawyers who have helped with these sales, according to four people who have seen some of the subpoenas. The people asked not to be identified because the subpoenas are part of confidential legal negotiations.

The demands for information began last year, and companies have continued receiving them in recent months, the four people said.

Nick Morgan, a former lawyer in the S.E.C.’s enforcement division, said that according to his contacts in the industry, the subpoenas had gone out to as many as 80 companies and individuals. Mr. Morgan, who is now a lawyer at the Paul Hastings firm, said those numbers would make this one of the broader regulatory sweeps he had seen.