Wall Street's top regulator is not sold on the prospects of crypto, at least right now.

Between the advent of decentralized finance, sustainable altcoins, and non-fungible tokens, the always gyrating and loosely overseen world of digital assets has proved to be a wealth of innovation since Satoshi Nakamoto pseudonymously dreamed up Bitcoin more than a decade ago. And yet it has also become home to frauds, potential illicit trading schemes, and promoters pushing tokens onto unsuspecting investors—a pattern of behavior that has led to a general acknowledgement across the cryptoverse, Wall Street, and Washington, D.C., that regulation is needed.

One of the leading voices in that charge has been U.S. Securities and Exchange Commission Chair Gary Gensler.

A veteran financial regulator and former partner at Goldman Sachs, Gensler has been an outspoken proponent in his short time at the agency for stricter investor-protection guardrails in the crypto markets, which now span thousands of coins that have a combined value of about $2.6 trillion. Until that happens, crypto "is unlikely to reach whatever potential it has," the SEC chair tells Fortune. "Technologies don't long survive outside of public policy frameworks."

Nominated to lead the SEC by President Joe Biden, Gensler’s appointment was met with optimism from crypto enthusiasts in early 2021. The former head of the Commodity Futures Trading Commission had been teaching courses on financial technology, including crypto, at the Massachusetts Institute of Technology after all—indicating a technological savviness about crypto that has been lacking in some parts of Washington. So executives across the industry had come to believe that the newly minted SEC chair was unlikely to bring a hammer down on the space.

Gensler, now six months on the job, has pulled in what many see as the opposite direction, though.

While the SEC chair has expressed a belief that the technology underlying cryptocurrencies can become a “catalyst for change,” Gensler has more often spoke of the crypto markets as the Wild West. On several occasions, Gensler has equated the proliferation of cryptocurrencies to the wildcat banking era of the 1800s, when lenders were able to freely issue their own currencies with little oversight coming down from the federal government.

The SEC has yet to pursue any specific crypto-related rules, as it awaits more help and authority in its push to better protect investors who are active in the asset class. For now, though, the regulator is focusing its foray into the crypto markets on what is a seemingly simple question: Are the tokens being offered on crypto platforms securities? The answer to whether something classifies as a security lies in what is now known as the Howey Test.

Born out of a 1946 Supreme Court case involving a company called W.J. Howey that was offering investors a chance to buy real estate contracts in a Florida orange grove, the test defines an investment of money as a security if it is put into a “common enterprise with a reasonable expectation of profits to be derived from the efforts of others,” according to the SEC. The regulator was given further authority to determine what is a security decades later when Justice Thurgood Marshall wrote that Congress painted with a “broad brush” in designing the basis for U.S. securities laws. Howey has since been used to classify everything from receipts on scotch whiskey barrels in the 1960s to parts of the peer-to-peer lending market in the 2000s as securities.

The SEC has taken a close look at whether cryptos classify as securities plenty of times before Gensler. Former SEC Chairman Jay Clayton, who headed up the agency under then President Donald Trump, helped lead a widespread crackdown on the initial coin offering bubble in 2017 under the same premise.

But Gensler is ratcheting up the pressure on the industry, telling Fortune that “it’s just a matter of probabilities” that the more tokens a platform offers, the more likely they are to be dealing in securities. And while the SEC chair has encouraged companies to come in and talk about their products for more insights, Gensler makes it clear that there are no exceptions as what will come next.

“If you are offering securities, we’re going to tell you,” Gensler says. “We’re not going to say that you’re okay just telling us about it. No, you’ve got to come within the investor laws that we have in this country.”