The agency had found that Francis V. Lorenzo, the former director of investment banking at a Staten Island brokerage firm, had misled investors about Waste2Energy Holdings’ assets while trying to sell $15 million of debt for the company. Mr. Lorenzo forwarded emails at the direction of his boss that said the company had $10 million in assets, when in fact its assets were worth less than $400,000.

Rather than charge him with being an accomplice to fraud, the S.E.C. accused him of being what is known as a “primary violator” of the main antifraud provision, Rule 10b-5.

Mr. Lorenzo argued that the Supreme Court’s 2011 decision in Janus Capital Group v. First Derivative Trading limited liability for misleading statements to those who “make” the statements, not those who help put the statements out to investors. The court said in its pithy ruling in the Janus case: “One ‘makes’ a statement by stating it.” In other words, only the speaker can be held to violate Rule 10b-5.

The Janus case, however, involved a private securities fraud class action, not an enforcement action by the S.E.C. So instead of limiting the main antifraud provision to only those that make the misleading statements, the court found in the Lorenzo case that “it would seem obvious that the words in these provisions are, as ordinarily used, sufficiently broad to include within their scope the dissemination of false or misleading information with the intent to defraud.” In other words, by participating in sending out false information, Mr. Lorenzo was culpable for engaging in a fraudulent scheme.

The court concluded its opinion by pointing out that “Congress intended to root out all manner of fraud in the securities industry. And it gave to the commission the tools to accomplish that job.” The key tool to fight fraud is Rule 10b-5, and the agency can now pursue a wide range of cases in which misleading information is given to investors, even if the person charged cannot be said to have actually made the statement.