Four things to know about the 'paper crude' futures collapse

After multiple investors in a crude-oil futures trading product sold by a major Chinese bank suffered huge losses due to the collapse in global oil prices earlier this week, a blame game has begun.

Some of the investors believe that Bank of China (BOC), one of the country's four largest state-owned commercial lenders, should take responsibility for the losses due to design defects in its product and its flawed risk management. Up to now, the bank has not actually addressed such complaints.