(Yicai) Oct. 11 -- Shares of Aima Technology Group, one of the first makers of electric bicycles in China, tumbled after chairman and main shareholder Zhang Jian was detained by police and placed under investigation.

Aima [SHA: 603529] ended 6.9 percent lower at CNY32.07 (USD4.54) a share in Shanghai today, after earlier dropping by the 10 percent exchange-imposed daily trading limit.

Zhang, who is also Aima’s general manager, was detained by police for investigation on Oct. 9, the Tianjin-based company announced yesterday, without revealing any reason for the probe. He has a 68.8 percent stake in Aima, according to the firm’s semi-annual earnings report.

Other senior managers are performing their duties as usual, and Zhang’s detention will not significantly impact the company’s operation and production, Aima noted, adding that its controlling structure has not changed.

China is the world’s largest market for e-bikes and scooters, driven by urban mobility needs and environmental concerns.

Aima, whose business spans e-bikes, mopeds, and motorcycles, reported a first-half net profit of CNY950 million (USD134.4 million) on revenue of CNY10.6 billion (USD1.5 billion), up 6.2 percent and 3.7 percent, respectively, from a year earlier. Overseas income surged 41 percent to CNY120 million.

Editor: Futura Costaglione