Tokyo, Nov 24 (IANS): Shares of Mitsubishi Materials, a division of one of Japan's biggest conglomerates, plunged over 8 per cent on Friday on the Tokyo Stock Exchange after admitting that its subsidiaries had falsified technical specifications of their products.

At 10.30 a.m., an hour and a half after the morning trading session started, shares of Mitsubishi Materials fell 345 points, down 8.44 per cent to 3,745 yen, reports Efe news.

On Thursday, the Japanese company acknowledged that three of its subsidiaries had falsified specification data about their products, including copper and aluminium sold to major industries like aerospace, automobile and power generation.

Mitsubishi Materials admitted that the problem affected products sold between April 2015 and September 2016, adding that the company already contacted 40 of more than 250 affected customers.

The Japanese company plans to hold a press conference later on Friday to explain in detail the scope of this case, which comes after the Kobe Steel domestic steel company acknowledged in October that it had detected false inspection data for its aluminium, copper, steel and iron products.

Irregular practices, which affected products sold to hundreds of companies around the world, included the handling of inspection certificates to make it appear that the technical data complied with requirements, the falsification of labels or even the omission of inspections.