SINGAPORE (Jan 3): ISR Capital, whose shares have been suspended by the Singapore Exchange, said that its executive director and CEO Quah Su Yin has resigned with effect from Dec 31 2016.

Quah, who was appointed to the CEO role in April 2011, has quit to “focus on family business”, said the company in an announcement made in the name of executive chairman Chen Tong.

Prosecutors have linked ISR Capital to John Soh Chee Wen, an alleged mastermind of the penny stock crash of October 2013.

(See also: Prosecutors confirm links between ISR Capital and John Soh)

Besides Soh, two other individuals have also been charged.

(See also: Next bail hearing of John Soh to be held on Jan 6)

They are Goh Hin Calm, interim CEO of Ipco International, as well as Quah Su Ling, the former CEO of the same company. The two Quahs are sisters.

Shares of ISR Capital surged some 4,000% over the past year since it announced plans to acquire a 60% stake in a Madagascar rare earth concession for $40 million in July.

The same stake changed hands for just 3.7 million euros ($5.6 million) last November.

On Nov 24, the day Soh and Quah Su Ling were brought into custody by the authorities, shares of ISR crashed by 55% to 12.7 cents. The stock was later suspended on Nov 27.

On Dec 7, the Monetary Authority of Singapore and the Commercial Affairs Department commenced investigations on ISR Capital.

Prior to Quah, the most recent resignation from ISR Capital was that of Chan Sing En, CEO of its subsidiary Dynamic Return (Singapore) on Dec 23.

(See also: Chan Sing En steps down as CEO of ISR Capital subsidiary Dynamic Return)

According to charge sheets released by the prosecutors, a brokerage account in the name of Chan was allegedly used by Soh to manipulate shares in the three penny stocks -- Asiasons (now renamed Attilan), Blumont and LionGold.

Quah Su Yin had earlier denied links between ISR Capital and these three companies.

Two other directors have also resigned from ISR Capital in recent months: Krishna Kumar Sivasubraniam on Nov 28 and Levin Lee Keng Weng on Dec 3.

In a separate announcement, ISR Capital said that 47-year-old Lee Ka Shao, who is now with a family office called PhiMattell, has joined the board today as a non-executive independent director.

Lee is a co-founder and chief investment officer of Cavenagh Capital and was previously with other financial institutions such as DBS Bank and JP Morgan.

“My appointment, first and foremost, is to safeguard and protect the interest of the public minority shareholders of ISR Capital whom may have been caught in a bind, especially with its recent stock trading suspension,” said Lee.

He said he will work with all stakeholders from regulators to minority shareholders to “achieve a desirable outcome as to the continuity and future of ISR Capital Limited’s operations and plans.”

Besides Chen and Lee, the two other existing directors on ISR’s board are executive director David Rigoll and independent director Kwok Wei Woon.