By Cheng Leng and Emily Chow

BEIJING/SHANGHAI (Reuters) – The Chinese regulator has asked commercial banks to halt new sales of a wide range of wealth management products that might lead to unlimited losses for investors, two sources told Reuters.

At the weekend, China Banking and Insurance Regulatory Commission (CBIRC) gave verbal instructions to banks to halt new sales of products that could trigger open-ended losses for investors, and requested reports on the outstanding size of related products, according to two direct sources who are familiar with the matter.

CBIRC’s move came nearly a week after heavy losses were recorded in a crude oil futures trading product sold by the country’s fourth-largest lender, Bank of China (BoC).

The CBIRC didn’t immediately respond to Reuters’ request for comment after working hours on Monday. BoC had no comment.

Last week BoC said it had settled trades for its crude oil futures trading product at a historic negative value of minus $37.63 per barrel, leaving mainly retail investors crying foul as they said the bank should have done more to protect their interests.

Some banks including BoC have been asked to conduct their own investigations into possible loopholes in their risk management since last week, a third source said.

Retail investors who shoulder the loss may have lost more than 9 billion yuan ($1.3 billion) from BoC’s crude oil product, financial news outlet Caixin reported on Sunday citing unnamed sources.

Industrial and Commercial Bank of China (ICBC) said on Monday that it will suspend all open positions for retail investor products linked to commodities futures, including crude oil, natural gas, copper and soybeans, from Tuesday.

It warned investors on Monday of a possible loss of all investments or cash deposits in these products due to commodities market volatility.

Shanghai Pudong Development Bank also said in a notice on Monday that it would suspend open positions for its copper and soybean trading products from the morning of April 28.

CME updated its systems to process negative prices earlier this month. In a notice dated April 8, it told clearing firms and clients that it had a plan in place “if major energy prices continue to fall toward zero in the coming months,” and if WTI crude oil, RBOB gasoline or heating oil futures fell between or below a certain range.

Oil prices have plunged this year due to the spreading economic impact of the coronavirus pandemic, a price war triggered by major producers Saudi Arabia and Russia, and a shortage of storage for excess oil, causing many crude oil-linked products to rack up major losses.

(Reporting by Cheng Leng and Emily Chow; Editing by Shivani Singh and Hugh Lawson)