Concerns about initial coin offerings among U.S. regulators and lawmakers were on full display during a U.S. Senate hearing on Tuesday.

"I believe every ICO I’ve seen is a security," Securities and Exchange Commission chairman Jay Clayton declared early on, perhaps setting the tone on a topic that would be raised numerous times during the roughly two-hour hearing. He largely echoed his past remarks on the subject, criticizing the “gatekeepers” of such offerings in the market today.

At one point, Massachusetts Senator Elizabeth Warren asked Clayton whether any ICO, past or future, had been subject to SEC registration.

"Not one," he answered to both.

Warren herself took a critical stance on the blockchain funding model (notable in part because her home state’s government has filed suit against ICO organizers in the past), returning again to the topic of unregistered ICOs just before the close of the hearing.

"I understand you to say it is a violation of the law" to do so, she remarked.

"Yes," Clayton replied.

Earlier in the hearing, Ohio Senator Sherrod Brown raised the point that, last year, ICOs raised billions of dollars worth of cryptocurrencies from investors. But of that amount, he asked Clayton, "how much of that...was raised in the U.S.?"

Perhaps unsurprisingly, the SEC chairman couldn’t offer a direct answer.

"It’s not clear," he told the senator. "It’s hard to get a number on that because this has been conducted on largely an unregulated basis. But I imagine, Senator, a significant enough portion that we should be paying attention.”

Ultimately, according to Clayton, some of those acting in the space are doing so even with the knowledge that they aren’t adhering as close as they ought to SEC regulations.

"I'm very not happy that people are conducting ICOs when they should know they should follow the private placement rules," he remarked during a back-and-forth with Senator John Kennedy.

That said, the SEC chair also made the point he wants, from a regulatory perspective, to separate cryptocurrencies from those digital assets that are clearly securities under U.S. law.

He remarked:

Image by Stan Higgins for CoinDesk