SINGAPORE - Asti Holdings executive chairman and chief executive Michael Loh Soon Gnee is resigning from the semiconductor manufacturer and its listed units Advanced Systems Automation (ASA) and Dragon Group International (DGI) due to unspecified "personal reasons".

Mr Loh last day of service has not been announced, but he will be transitioning his duties within the next 12 months, the companies said in regulatory filings on Sunday night (April 7). Mr Loh is currently CEO of ASA, an Asti associate company, and CEO and executive chairman of DGI, an Asti subsidiary.

The boards added that they are currently identifying and reviewing internal and external candidates in its search for Mr Loh's successor. He will also continue to work closely with the board to achieve a smooth transition, the companies said.

The companies noted that with Mr Loh stepping down as CEO, the individual business units or subsidiaries will still have senior management who have been working with the companies between eight to 25 years.

Mr Loh has served as director of Asti since Oct 23, 2003 and was appointed CEO of the company on July 1, 2013. He has also served as a director of ASA since July 19, 2006 and was appointed CEO on Nov 12, 2010. He has been director of DGI since Oct 23, 2003, and was appointed CEO on July 1, 2008.

Asti shares last traded at 4.5 cents, down 2.2 per cent, or 0.1 cent on April 5, while ASA shares closed flat at 0.1 cent on the same day.

Shares of DGI are currently suspended pending a mandatory delisting after the company failed to meet minimum levels of profitability and market valuation under the Singapore Exchange's Mainboard listing rules. Asti, as the controlling shareholder of DGI, is required to make an exit offer to other DGI shareholders.