The logo of Samsung Electronics is seen at its office building in Seoul, South Korea, March 23, 2018. REUTERS/Kim Hong-Ji

SEOUL (Reuters) - South Korean prosecutors on Thursday said they have indicted nine people on suspicion of leaking Samsung Electronics Co Ltd flexible display technology to a Chinese company.

The Suwon District Prosecutors’ Office has charged the chief executive and eight employees of supplier Toptec Co Ltd for selling information earlier this year about Samsung’s organic light-emitting diode (OLED) panels.

The group are accused of forming a separate shell company that received information on the use of equipment and drawings of panels obtained from Samsung subsidiary Samsung Display, and which sold some of the documents in China for 15.5 billion won ($13.85 million), the prosecutors office said.

Toptec, which produces automated equipment to make mobile phone display panels, denied any wrongdoing.

“Our company has never provided Samsung Display’s industrial technology or business secrets to a Chinese client. Our company will fully cooperate with legal proceedings to find the truth in court,” Toptec said in a statement.

Shares in Toptec tumbled 20 percent.

A Samsung Display spokesman said the indictment was “regrettable” and that the firm would increase efforts to protect technology.

Prosecutors said Samsung Display invested 150 billion won over six years to develop the leaked technology of 3D lamination, which they said was “a national core technology”.

Samsung dominates the market for small and mid-sized OLED displays and is a supplier of Apple Inc.