On Wednesday, Reuters reported that Qingdao Port was conducting an investigation about whether copper, aluminum and iron ore piled up in its warehouses were used as collateral several times to obtain financing from various lenders. The port is said to have stopped export of such cargo.

On Thursday, the 21st Century Business Herald, a Chinese language newspaper, quoted insiders close to the matter as saying that the investigation focused on Decheng Mining, a Qingdao-based private bauxite importer.

The cargo involved was 100,000 tons of aluminum oxide and about 3,000 tons of copper. Four banks, including Standard Chartered Plc, were said to be involved and the lenders collectively had an exposure of over 1 billion yuan ($162 million), the report said.

Qingdao Port, however, said its operations have not been hampered by the ongoing investigation.

"Everything is running normally," the operator's chairman, Zheng Minghui, stressed during the company's listing ceremony on Friday. Zheng declined further comment on the issue.

"The investigation is not a big deal to the port," said Kenny Tang, general manager of the securities and asset management business at AMTD Financial Planning Ltd, a subsidiary of the Hong Kong-based Cheung Kong Group. "Investors are not keen on the shares as the overall outlook for commodities is not that optimistic.

As the GDP growth rate in China slows down and the country invests less in infrastructure but more on innovation, the demand for commodities such as iron ore is likely to remain subdued." However, Qingdao Port's business will remain stable in the long term due to the soft landing of the economy, Tang said.

Top 10 trading partners of the Chinese mainland	Qingdao Port: Shipments unaffected by investigation