For more than a decade, the pioneers of the cryptocurrency industry envisioned digital coins as an alternate branch of finance, a renegade sector that would operate outside the reach of big banks and government regulators.

But as digital currencies like Bitcoin and Ether became more mainstream, the crypto industry collided with a 1946 Supreme Court decision that created what is known as the Howey Test, a legal analysis that determines when a financial product becomes subject to the same strict rules as stocks and bonds.

In recent years, regulators have seized on that legal precedent to argue that cryptocurrencies are just another security, like shares of Apple or General Motors. The crypto industry has fought back, leaving it in a legal gray zone with an uncertain future in the United States.

Now the long-running dispute is edging closer to a resolution, as federal judges begin weighing in on a series of lawsuits by the nation’s top securities regulator against some of the largest crypto firms. This month, judges held hearings in two of the most consequential cases, which could dictate whether the multitrillion-dollar crypto industry can continue growing in the United States.

The legal battles are “an existential issue for crypto,” said Hilary Allen, a professor at American University who specializes in financial regulation.

The court fights intensified over the last 18 months, as the Securities and Exchange Commission brought enforcement lawsuits claiming that crypto companies were operating as unregulated securities businesses. In response, the industry argued that laws governing Wall Street trading shouldn’t apply to digital currencies. Both sides scored early court victories that left the matter unsettled.