Aluminium giant Rusal shares collapse after US sanctions

Shares in Russian aluminium giant Rusal collapsed on Monday after Washington targeted it with sanctions, putting the metals major at risk of defaulting on part of its debt.On the Hong Kong stock market, one of the exchanges where Rusal's shares are listed, it closed 50 percent down at HK$2.34.The fall wiped more than 3.5 billion euros ($4.3 billion) off the market capitalisation of the company which is headed by billionaire Oleg Deripaska and accounts for some seven percent of the world's alumin