Troubles at the exchange are one of many factors contributing to turbulence in China's financial markets, as a slowing economy exposes the weaknesses of the country's debt-driven growth.

Investors have been protesting for weeks after the Fanya Metals Exchange in July ceased making payments on financial investment products. The exchange, based in the southwestern city of Kunming, bought and stockpiled minor metals such as indium and bismuth, while also offering high interest, highly-liquid investment products from its offices in Shanghai and its financing branch in Kunming.

The head of a Chinese exchange that trades minor metals was captured by angry investors in a dawn raid and turned over to Shanghai police, as the investors attempted to force the authorities to investigate why their funds have been frozen.

Some investors flew in from faraway cities to join hundreds more surrounding a luxury hotel in Shanghai before dawn on Saturday. When Fanya founder Shan Jiuliang attempted to check out, they manhandled him into a car before delivering him to the nearest police station. Shanghai police took Mr Shan into custody and promised to work with local authorities in Yunnan province to investigate what has happened to investors' money. They later released him without charge.

The demonstrations in Shanghai and Kunming and the exchange's unusual accumulation of several years' supply of some metals have so far failed to attract much public attention from regulators. A report by the local regulator identifying the exchange as one of the bigger investment risks in Yunnan was redacted to remove reference to Fanya late last year.



More from the Financial Times:

China's 'little tigers' present political challenge

China hardly the ideal model for market behaviour

China: unfavoured nation

The exchange began to experience liquidity problems this spring. Fanya is estimated to hold several years' supply of minor metals used in some high-tech and military applications, which it purchased at above-market prices. The exchange's travails are pressuring prices for some of these metals, as traders anticipate it will have to sell its stockpile.

The exchange, which has acknowledged it has problems, is backed by several of China's minor metals miners. It has said it has found a buyer but won't identify the company. Mr Shan "was deceiving us. He admitted to us that there is no buyout group," said one disgruntled investor surnamed Gu, who participated in the rainy early morning raid.

Mr Shan has been holding regular meetings with exchange backers since problems first surfaced this spring and was on the way to Guangzhou for a business trip when captured. Among other businesses he heads the Hong Kong-listed animation studio Imagi International Holdings. He formerly led the Bohai Commodity Exchange, which traded iron ore among other products.

Read More

Fanya denounced the weekend's raid. "Violent acts against president Shan and our employees or the disturbance of our work are destructive of our work around solving the crisis. This will only allow forces behind the scenes to profit and will greatly harm interests of all members," it said on its website after Mr Shan's capture.

Mr Shan has not responded to FT attempts to contact him. Many investors told the FT they were attracted to Fanya financial products because it advertised on CCTV, the national broadcaster. Despite its current problems its financial products are still promoted on the high-speed train from coastal city Tianjin to Beijing.