Singapore’s Straits Times Index reached a new 52-week high last week, reflecting strong investor confidence. However, not all top-tier equities shared in the optimism, with certain blue-chip stocks faltering even as others surged.

The performance of Singapore’s large-cap companies in September 2025 painted a mixed picture. While the broader market posted gains, three notable blue-chip stocks stood out as significant underperformers. The question for investors isn’t just “which stocks declined?” but rather “are these temporary challenges or indicators of deeper issues?”

Below, we examine the three biggest blue-chip decliners of the month, providing context on their struggles and what lies ahead.

For perspective, the STI remained flat during September, meaning these stocks lagged behind the broader index for the month.

Singtel: Total Return of -4.2% in September 2025

Singtel, commonly known as Singtel, is Singapore’s leading telecommunications company, with operations across Asia and Australia. However, its subsidiary Optus in Australia has been the source of headline-catching disruptions.

On 28 September 2025, Optus faced a network outage that affected around 4,500 users, compounding its struggles from a similar failure just two weeks prior. The incident occurred as Singtel’s CEO Yuen Kuan Moon was summoned by Australian authorities to address the earlier outage from 18 September, raising concerns about regulatory scrutiny.

This is particularly impactful since Optus contributed roughly half of Singtel’s revenue for the fiscal year ending 31 March 2025 (FY25). Although Optus had shown signs of recovery—with operating profits surging 55% year-on-year to A$446 million—these setbacks could curtail its positive trajectory if Australian regulators impose penalties or require infrastructure investments.

Despite recent headwinds, Singtel’s stock remains near a decade-wide high, as investors remain optimistic about the company’s strategic plans. These include recycling capital and distributing dividends worth 70-90% of underlying profits, alongside an additional value realization dividend ranging from S$0.03 to S$0.06 annually. Notably, Singtel delivered the third-best returns in August 2025 before this reversal.

CapitaLand Investment Limited: Total Return of -2.5% in September 2025

CapitaLand Investment, or CLI, is Asia’s heavyweight in real estate investment management, overseeing a staggering S$117 billion in funds under management (FUM) as of mid-August 2025.

For 1H’25, CLI’s revenue dropped 24% year-on-year to S$1.0 billion. While its Fee Income-related Business (FRB) remained stable with S$564 million in revenue, its Real Estate Investment Business (REIB) saw a sharp decline of 43% to S$519 million due to the deconsolidation of CapitaLand Ascott Trust (SGX: HMN), which removed S$322 million in revenue. Excluding this factor, however, CLI’s revenue grew by 7%, emphasizing improved fee income and lodging performance.

PATMI for the period fell to S$260 million, a 12% year-on-year decline, attributed to asset divestments, decreased fund performance fees, and the absence of one-off tax benefits seen in 2024.

CLI has been bolstering its capabilities with acquisitions, including a 40% stake in SC Capital Partners (adding S$11 billion to FUM) and taking full ownership of Wingate Group Holdings (adding another S$2 billion). The company targets growing its FUM to S$200 billion by 2028.

Despite these setbacks, CLI remains focused on long-term growth, paying an ordinary dividend of S$0.12 per share for FY24 alongside a special distribution of CapitaLand Integrated Commercial Trust (SGX: C38U) units. Interim dividends were not declared for 1H’25, consistent with its policy of paying annual dividends.

Wilmar International: Total Return of -3.4% in September 2025

Wilmar International, a global agribusiness powerhouse, faced a regulatory setback in Indonesia. On 25 September 2025, the company was ordered to pay nearly US$710 million in fines by the Indonesian Supreme Court, overturning an earlier decision to acquit three of its subsidiaries.

This penalty is expected to result in a loss for 3Q’25; however, Wilmar anticipates profitability for the full year. The financial impact of the fine appears manageable, as the company generated US$1.3 billion in free cash flow during 1H’25—sufficient to cover the loss, although some might argue this capital could have been better allocated toward reducing its net debt, which stood at US$22.3 billion as of 30 June 2025.

Wilmar’s integrated business spans the entire commodities value chain, with over 1,000 manufacturing plants across 50 countries. It categorizes its operations into four primary segments: Food Products (consumer goods and bulk edible oils), Feed and Industrial Products (oils, grains, sugar merchandising), Plantation and Sugar Milling (cultivation and milling), and Others (logistics and investments).

While the immediate financial fallout from the fine is manageable, investors must keep an eye on potential additional penalties, the impact on Wilmar’s credit ratings and borrowing costs, and the possibility of similar challenges arising in other markets where the company operates.