Singapore stocks edged down on Friday as investors booked profits ahead of the weekend, with declines spread across the board, while Asian shares flat-lined despite another record closing high in US markets.

The benchmark Straits Times Index fell 0.3% to 3291.82, after a strong comeback the previous day, though it gained 0.4% on the week.

MSCI's broadest index of Asia-Pacific shares outside Japan was flat, deflecting optimism in US markets as the S&P 500 index posted its third record closing high in four sessions.

Trading among banks dominated the Singapore index, with all three banks among the top traded stock on the bourse by value. OCBC shares were up 0.2%, UOB shares rose 0.04% and DBS fell 0.4%.

Singapore Telecommunications retreated from 9-month highs, falling as much as 0.8% to $3.86. Shares of the telecommunication firm had gained as much as 1.6% on Thursday after Chinese e-commerce giant Alibaba Group Holdings said it was buying a minority stake in Singapore Post, in which SingTel is the largest shareholder.

Olam International bucked the trend, surging as much as 4.1% to $2.29 in early trading, before falling back down to $2.23. Olam shares had shot up 11.8% in March to hover at $2.23, after state investor Temasek Holdings made an offer to buy out Olam, before plunging 4.5% after the offer expired on Monday.

Among small-caps, shares of Tat Hong Holdings plunged 5.3% to an intra-day low of $0.81, after the crane rental company reported quarterly earnings that came in worse than expected.

CIMB downgraded its rating on the stock to "reduce" from "hold", with a target price of $0.72. "While there might be cautious optimism over projects deployment going into FY15, we think that margins from intense competition may cap overall performance," the brokerage said.