More than 60,000 individual investors participating in the scheme lost deposits worth as much as 4.2 billion yuan, it said. Each one third of the total had invested over 50,000 yuan.
The crude oil "bao" of the Bank of China is sold to individual customers and is associated with futures contracts for domestic and foreign crude oil, including West Texas Intermediate (WTI) and Brent.
Last week, the Bank of China settled trades after WTI futures prices for the first time dropped below $0 and ended at minus $37.63 per barrel as traders paid to get rid of their oil.
The bank held long positions between 24,000 and 25,000, with each position having the equivalent of 1,000 barrels, leading to an estimated loss of 5.8 billion yuan, Caixin said.
Last Friday, the bank said it was "deeply disturbed" by the losses incurred by its investors, and blamed the global oil market volatility caused by the global coronavirus pandemic.
($1 = Yuan 7.0813)