Chinese research analysts, whose work depends upon trade data from the world’s top metal producing and consuming country, told Metal Bulletin they have been only granted very limited access to trade data since the end of April.

“The last files we got are the March monthly data. We are all worried if the suspension in data publication carries on. Now our research can only be based on estimates and market news,” a zinc and lead analyst in China said.

China’s customs department used to sell trade data - which is now referred as a “problematic practice” in its latest National Audit Report published on its website on Wednesday.

A major copper smelter in China, which used to receive copper concentrates exports and imports data on a monthly basis, told Metal Bulletin it received earlier this month a notice from customs explaining the reason for the delayed publication of April data.

The notice, seen by Metal Bulletin, said Chinese customs understands the importance of trade data transparency to the economy and is currently “adjusting the solution” to publishing data. Yet the April data is still not available to the market and no timetable for the publication of data has been given.

A number of market source speculated that the data is being withheld to introduce some opacity to China’s import/export data because of the continued trade disputes between China and the United States. Earlier, the Chinese government retaliated to prior US import tariffs of 25% on $50 billion of Chinese products by announcing 25% import tariffs on $34 billion of US goods.

Trade relations are likely to become worse in the short term before getting any better, Metal Bulletin analyst Boris Mikanikrezai said.

“Hopefully data publication will resume after the tension eases,” the above smelter source said.

While import and export data for some copper and aluminium products are available, the market does not have access to any detailed trade data of metals including the countries of origin and export destination for April and May.

For instance, the aggregate data “Unwrought copper and copper products” for May is still available but the separate data for copper raw materials, such as the amount of copper concentrates and blister copper traded are no longer being published, a copper analyst said.

No import and export figures have been available for refined and intermediate products of zinc, lead and nickel since the end of April, the source added.

Metal Bulletin’s Shanghai office also ceased to receive any detailed trade data at the end of April.

Chinese customs said income from data provision to external buyers totaled 5.63 million yuan ($867,363) from 2016 to 2017, according to the national audit report on Wednesday.