SINGAPORE, Sept 5 — Singapore police have warned of a resurgence in “pump and dump” stock manipulation scams, with 21 cases involving overseas-listed companies reported in the past two months.

One case involving a Hong Kong-listed company resulted in losses of more than S$700,000 (RM2.82 million), Singapore-bsed The Straits Times reported police saying in an advisory today.

Scammers typically pose as investment experts or trading mentors on social media and messaging platforms such as WhatsApp, building trust before recommending supposedly high-potential shares listed in Hong Kong or the US.

They then drive up demand and prices through coordinated buying before selling their own holdings at inflated prices, causing the shares to plunge and leaving victims with heavy losses.

Police said scammers may create chat groups using Singapore-registered numbers and use accomplices posing as administrators to pressure victims into buying the recommended shares and provide proof of their trades.

In one case, five victims collectively bought 1.037 million shares in a Hong Kong-listed company, whose price fell almost 75 per cent within a week, causing combined losses of more than HK$4.6 million (RM2.42 million).

In another case, a Singaporean couple put S$650,000 (RM2.62 million) into a Hong Kong-listed company and suffered more than S$500,000 (RM2.02 million) in paper losses.

Scammers may also promise to reimburse victims after the share price collapses, but become uncontactable or offer excuses when compensation is sought.

Police last warned about the scam variant in 2021 and urged the public to be wary of unsolicited stock tips and high-pressure “buy now” tactics.

They also advised investors to be particularly cautious about overseas-listed shares with low liquidity and small market capitalisation, which can be more vulnerable to price manipulation.

“No investment or trading strategy can guarantee profits,” the police said.