Singapore's Straits Times Index tumbled on Monday to start the week on a low note after the Monetary Authority of Singapore disclosed that it will leave monetary policy settings unchanged.

During the day, the benchmark index ranged between 3,137.49 and 3,172.45, ending 0.61% or 19.22 points lower at 3,140.31.

The Monetary Authority of Singapore has left its monetary policy unchanged for the third month in a row, with the city-state's central bank expecting Singapore's economy to strengthen in 2024. In its January monetary policy statement released Monday, MAS said it will "maintain the prevailing rate of appreciation of the Singapore dollar nominal effective exchange rate (S$NEER) policy band."

Separately, The Singapore Manufactured Products Price Index fell 1.1% on a month-on-month basis in December 2023, extending the 2.5% decrease in the preceding month, data released by the Department of Statistics Singapore on Monday showed.

Furthermore, Singapore's Import Price Index fell 2.1% month on month in December 2023 after a 2.4% drop in November, the Department of Statistics reported Monday.

In company news, CapitaLand Ascott Trust (SGX:HMN) posted a distribution per stapled security of SG$0.038 in the second half of 2023, up 14% from SG$0.0333 in the year-ago period, sending the trust's shares up 2% at market close.

Lion Asiapac (SGX:BAZ) closed over 17% higher on Monday, even as the company disclosed that it expects to post a loss in the fiscal second quarter and half year ended Dec. 31, 2023.

Matex International (SGX:M15) shares slipped nearly 4% on Monday's close, as the company acquired a 19.12% stake in Singapore-based AR Bioenergy Tech, which was incorporated to convert low-value biomass to high-value carbon and activated carbon products, for SG$1.3 million.