Macau casino shares have plunged amid the arrests of 11 people over alleged links to cross-border gambling and money laundering, with Suncity Group Holdings Chairman Alvin Chau believed to be among those detained.

Suncity is Macau’s biggest junket operator, and its Founder Chau is widely believed to be the 47-year-old businessman that police said they were questioning on Sunday. An arrest warrant was reportedly issued for Chau on Friday by eastern Chinese city Wenzhou, for operating gambling activities in mainland China, where gambling is illegal.

MGM China shares fell by 11%, with Wynn Macau and Sands China shares falling by 9% and 6% respectively, as investors fear both the short-term and long-term consequences of the arrests. Short-term issues involve potential loss of business, while long-term worries centre around the potential hardline stance that will be taken by authorities in Macau and mainland China to ensure such a situation doesn’t occur again.

Suncity Group shares meanwhile have been suspended from trading.

“Suncity accounts for over 50% of junket revenue in Macau, which accounts for roughly 50% of gaming revenues, so Suncity accounts for 25% of gaming revenues,” said Carlos Lobo, a Macau-based gaming consultant, as reported by Reuters.

“The impact on the gambling industry is huge... But Suncity is no longer too big to fail, the system will not collapse.”