MAS
MAS is unlikely to alter policy at this week's review. Reuters

Singapore's central bank is investigating several broking firms for suspected involvement in insider trading and market manipulation.

The Monetary Authority of Singapore (MAS) and the Commercial Affairs Department (CAD) seized documents from several broking firms and trading representatives as part of the probe.

Investigators conducted raids at several broking houses including DBS Vickers, Maybank Kim Eng, OCBC Securities and Philip Securities, the Business Times reported.

The Singapore Exchange (SGC) said it referred to MAS nine cases related to insider trading and six cases connected with market manipulation in the January to March quarter, Bloomberg reported.

MAS said in a statement it has joined the tax authorities and Singapore police in jointly investigating possible breaches of the Securities and Futures Act.

"The Monetary Authority of Singapore and the Commercial Affairs Department of the Singapore Police Force are jointly investigating possible contraventions of the Securities and Futures Act (Cap. 289) and have obtained documents and items from several broking firms and trading representatives. As investigations are ongoing, we are not able to provide further information," the MAS said.