Casino stocks plummeted as investors became increasingly concerned that one of the world’s most important gambling centers may be undergoing a major transformation.

On Tuesday, Macao announced a 45-day public consultation, which some worry could result in tougher rules for the lucrative gaming sector, as part of China’s ongoing crackdown on private enterprise.

Stocks in US casino firms that operate in Macao, China’s only legal gaming jurisdiction, plummeted as a result of the announcement. In Hong Kong, Sands China was down more than 32%, Wynn Macau was down more than 28%, and MGM China was down more than 26%.

Macao’s economic and finance secretary, Lei Wai Nong, told reporters that the administration of the semi-autonomous Chinese region was contemplating reforms in nine areas. The number of gaming licenses given and their tenure, as well as a tighter evaluation process for licensing operators and employee welfare, are among these topics.

Macao officials are also considering shifting Macao’s main source of income to “non-gambling elements.” This includes the establishment of non-gambling attractions to bring in more international tourists.

“[The Macao] government has decided to conduct a comprehensive review and improvement of the existing legal system on the basis of past regulatory experience, the current situation of the gaming industry and Macao’s economic development,” officials said in a statement.

Macao’s economy is largely dependent on gambling, and the city-state relies on millions of visitors mostly from mainland China. The Covid-19 pandemic has threatened Macao’s economic paradigm, forcing it to review its economic strategy.