Indonesian Blue Chip Stocks Surge in August: Who Is the Strongest?

A number of large-capitalisation stocks recorded double-digit price increases over the past month. However, not all of these gains were supported by inflows of foreign investor funds.

From around 900 listed companies, the screening required a market capitalisation above Rp20 trillion and a gain of more than 15% over the past month since Wednesday (26/8/2026). Companies included in the HSC list were also excluded from the selection because they are considered too volatile and at risk of sharp declines and increases due to the high concentration of share ownership by business owners.

Of the ten selected blue chip candidates, only four stocks recorded foreign net buy of more than Rp1 billion, namely TINS (PT Timah Tbk), ICBP (PT Indofood CBP Sukses Makmur Tbk), GGRM (PT Gudang Garam Tbk), and INKP (PT Indah Kiat Pulp & Paper Tbk).

Meanwhile, ISAT (PT Indosat Tbk), AADI (PT Adaro Andalan Indonesia Tbk), NCKL (PT Trimegah Bangun Persada Tbk), TAPG (PT Triputra Agro Persada Tbk), EXCL (PT XLSMART Telecom Sejahtera Tbk), and KLBF (PT Kalbe Farma Tbk) did not pass the foreign net buy screening of above Rp1 billion.

Calculations in US dollars use an assumed exchange rate of US$1 at Rp17,700.

Of the ten stocks, the discussion focuses on ISAT, EXCL, NCKL, and TINS. These four stocks offer four different stories: telecommunications business growth, merger synergies, index rebalancing, and rising commodity prices.

ISAT was the best-performing stock over one month. Interestingly, the increase of around 30.77% was not accompanied by material foreign net buy.

The most important driver for ISAT was the increase in ARPU (Average Revenue Per User) and data traffic. Subscriber numbers did not grow significantly, but revenue earned from each customer increased.

This condition shows that ISAT is beginning to have pricing power and is able to monetise data traffic better. The ARPU increase of 17.3% also occurred alongside data traffic growth of 19.9%.

Net profit soared 84.5%, but part of this came from a one-off gain related to the monetisation of FiberCo. After excluding this gain, core net profit still grew by around 36%.

Thus, ISAT’s performance remains strong even though headline profit growth appears higher due to non-recurring gains.

The FiberCo transaction funds provided additional liquidity for ISAT. However, management also raised the capital expenditure plan from around Rp13 trillion to Rp23 trillion for 5G and cloud development.

This means the market is not only assessing current performance but also incorporating expectations of digital business growth in the next period.

EXCL offers a different story from ISAT. The rise in EXCL shares largely reflects optimism about the outcome of the XL Axiata and Smartfren merger.

Around 92% of sites have been integrated. Gross synergy has also reached US$153 million, or around Rp2.71 trillion.

If the synergy target of US$250 million to US$300 million is achieved, the economic benefits of the merger could reach Rp4.43 trillion to Rp5.31 trillion.

The increase in blended ARPU to Rp47,100 shows that the customer monetisation process is beginning to improve. Normalised EBITDA and normalised net profit also recorded strong growth.

However, EXCL still posted a net loss of around Rp994 billion on an accounting basis. Depreciation expenses, integration costs, capital expenditure, and debt levels remain challenges.

A debt-to-EBITDA ratio of around 5.2 times shows that the merger process carries significant balance sheet risk. Therefore, the market is still waiting to see whether the synergies can truly reduce costs and improve cash flow.

NCKL received two catalysts simultaneously: net profit growth and the inclusion of its shares in the LQ45 and IDX80 indices.

Index changes can trigger buying from mutual funds, ETFs, and investment managers that use the indices as benchmarks. Such buying does not have to come from foreign investors because domestic institutions also make portfolio adjustments.

From the financial statements, revenue grew 21.3% and net profit rose 41.7%. However, gross profit and EBITDA actually declined.

Cost of goods sold increased more than revenue. This indicates cost pressure and margin decline in core operations.

Net profit growth was also supported by contributions from associates and other components. Therefore, investors should not only look at the 41.7% net profit growth.

Indicators to watch include nickel prices, gross profit, EBITDA, royalty expenses, production costs, and developments in the processing segment.

TINS has the most complete combination of catalysts. Tin prices rose, the global market experienced a supply deficit, revenue and profit soared, margins improved, and foreign investors made net buys of more than Rp1 trillion.

Tin demand is supported by the electronics and semiconductor industries. Around 50% of global tin consumption is used for solder.

The development of artificial intelligence, data centres, electric vehicles, energy storage, and electricity infrastructure has the potential to increase tin demand in the long term.

The price increase has flowed directly into the financial statements. TINS revenue increased 247%, EBITDA grew 363%, and first-half net profit reached 169% of the full-year target.

However, tin inventories in LME warehouses increased by 58.36%. This condition indicates that supply is beginning to recover and could trigger a normalisation of tin prices.

The large foreign net buy also increases the risk of a crowded trade. If tin prices weaken and foreign investors turn to selling, the share price correction could occur more quickly.