The marble-mining company ArtGo was on track to be the world's best-performing stock for firms worth than $1 billion. On Thursday morning, however, its shares tanked 98%, and the company saw $5.7 billion in market value wiped out before trading was suspended.
The Hong Kong-listed stock plummeted after MSCI dropped its plans to include ArtGo in its influential indexes, a development first reported by The Wall Street Journal.
