Macau casino operator stocks plummeted by as much as a third on Wednesday, losing around $14 billion in value, as the government kicked off a public consultation that investors fear will lead to tighter regulations in the world's largest gambling hub. With Macau's lucrative casino licences up for rebidding next year, a government proposal to revise the city's gaming law spooked a Hong Kong market already slammed hard into the red by a broad Beijing regulatory crackdown, across sectors from technology to education and property, that has sliced hundreds of billions of dollars off asset values. Wynn Macau led the plunge, falling as much as 34% to a record low, followed by a 28% tumble for Sands China . Peers MGM China, Galaxy Entertainment , SJM and Melco Entertainment all fell heavily, bringing the drop to HK$109 billion ($14 billion). The slump came after Lei Wai Nong, Macau's secretary for economy and finance, late on Tuesday gave notice of a 45-day consultation on the gambling industry starting Wednesday, saying there were still some deficiencies in industry supervision.