With Congress moving slowly, regulators are preparing rules that could reshape the crypto market now—yet leave businesses exposed to another political reversal.

In the United States, progress on a sweeping cryptocurrency bill has stalled, meaning that President Donald Trump’s federal regulators may take on a key role in shaping rules for digital assets. At the same time, decisions by the U.S. Securities and Exchange Commission (SEC) and the Commodity Futures Trading Commission (CFTC) may prove temporary: future administrations could revise or repeal them.

Crypto companies have spent hundreds of millions of dollars over several years supporting legislative initiatives. The industry hoped to secure clear and stable legal conditions…