01 THE WEEK IN BRIEF
A rebound that did not last
The IHSG fell 3.09% as foreign investors sold a net Rp3.16tn of shares over five days, according to IDX. Thursday alone accounted for Rp1.49tn. The index gained 97.868 points on Wednesday, then lost 133.020 points by Friday. The bounce did not hold, and the selling continued.
The Fed raised rates on 16 September, before this trading week, and Bank Indonesia held its rate on 23 September. JISDOR rose 0.97% between the two Fridays, adding to the loss for an investor measuring returns in dollars without a hedge. These events give context, but the releases do not show why the IHSG fell.
Back below Tuesday’s close
The line joins daily closes, not moves during the day. Its scale runs from 6,200 to 6,480, not from zero. The dashed line marks the previous week’s close.
Daily closing prices
Each daily change compares the close with the one before it. The first row is the previous Friday’s close.
| Date | Close | Change on the day |
|---|
Calculating the weekly move
The percentage needed to recover is larger than the percentage lost because it starts from a lower index level.
02 RATES AND CURRENCY
A weaker rupiah added to the loss
Higher US rates can make risky rupiah assets less attractive, all else equal. BI kept its rate unchanged and described measures to steady the currency. The 187.5-basis-point gap is the BI-Rate minus the midpoint of the Fed’s target range. It is not a bond-yield spread or a return investors can earn. The currency comparison below uses BI JISDOR. This report does not include sovereign bond yields.
Comparing the policy rates
If dollar assets pay more, investors may want a higher return to hold Indonesian assets.
A weaker rupiah cuts the dollar return for an investor without a currency hedge.
Imports and dollar debt can cost more. The effect on exporters depends on their revenue, costs and hedges.
TRY YOUR OWN NUMBERS
What the weaker rupiah meant in dollars
BI JISDOR moved from Rp17,745 to Rp17,917 per dollar between the two Fridays. Combined with the IHSG price change, that gives a rough −4.02% return in dollars. Move either slider to try a different assumption.
How the currency calculation works
Start with a dollar amount W and two rupiah-per-dollar rates, S₀ and S₁. The final dollar amount is W × S₀ × (1 + RIDR) ÷ S₁. Dividing that result by W gives the percentage return shown above. The calculation uses decimal returns.
The five rows keep the observed IHSG return and vary the currency move. The highlighted row uses BI’s two JISDOR rates.
| USD/IDR change | USD return | What it means |
|---|
BI samples JISDOR transactions from 09:00 to 15:00 WIB and publishes the rate at 15:15. That is a different time from the stock market close. The −4.02% is a rough comparison using a reference rate, not a dollar return anyone could have locked in at the close. It leaves out dividends, fees, taxes, hedging and tracking costs. The other rows are scenarios.
Foreign selling persisted across all five sessions
IDX reports Rp3,155.08bn of foreign net selling for 21 to 25 September. It was the third straight week of net selling, bringing the three-week total to Rp9.46tn. Foreign investors were net sellers every day, and the five daily figures add up to IDX’s weekly total. Thursday alone made up 47.3% of the week’s net selling. These figures measure share trades by investor classification. They do not measure money leaving Indonesia or how many IHSG points foreign investors caused.
Thursday saw the most selling
Net foreign buying of shares each day, in Rp bn. Buy value minus sell value. All five values are negative, shown on the same scale from 0 to 1,500.
Checking the daily total
| Date | Net foreign purchase |
|---|
IDX also reports Rp53.66tn of trading on the regular market and Rp6.23tn on the negotiated market. Its foreign net figure does not split purchases or sales between those markets, so these reports cannot tell us how much of the foreign selling happened in each one.
03 SECTORS AND TRADING
Ten sectors fell
Only consumer cyclicals ended the week higher, up 0.02%. That small gain is weak evidence of a broader recovery. Industrials fell 5.48%, infrastructure 4.10% and technology 3.96%. Materials and energy also fell despite a midweek bounce. These returns show where prices moved. They do not show which investors bought or sold.
How each sector did
All 11 IDX sector indices
| Sector | 21 to 25 Sep return |
|---|
These are price changes in each sector index, not points added to or taken from the IHSG.
Trading value per share fell 22.89%
Each bar divides weekly stock trading value by shares traded. The same scale, Rp0 to Rp600, applies to both weeks. The totals include regular, cash and negotiated markets.
Weekly trading activity
| Measure and unit | Previous week | This week | Calculated change | IDX figure |
|---|
The changes in trading value, share volume and trade count use exact weekly totals. The daily averages shown above are rounded. Market value uses the published levels. The Rp361tn fall in market value does not mean investors took that much cash out.
More shares traded even as trading value fell 21.32%. That fits a shift toward lower-priced shares, lower share prices, or both. It does not tell us why investors traded. To judge a recovery, watch whether trading value rises while foreign selling eases and more sectors join in.
04 BIGGEST MOVERS
Three stocks accounted for a third of the decline
IDX’s index-mover table puts BYAN, BBRI and BMRI together at 66.10 points of the IHSG’s net 199.267-point fall. That is about a third of the decline, before gains in other stocks offset some losses. The company questions below are things to check, not confirmed catalysts or price targets.
Three stocks that weighed on the index
These are points the three stocks took off the IHSG during 21 to 25 September. Each bar uses the same scale from 0 to 30 points.
Adding the three changes
Check coal prices and cash flow
BYAN fell 12.48% and took 28.09 points off the IHSG, more than any other stock in IDX’s table. To assess a recovery, look for evidence in coal prices, sales volume and cash flow. These market figures do not tell us how those parts of the business are doing.
Watch the cost and quality of loans
BBRI fell 4.83% and took 23.33 points off the IHSG. The next question is whether funding costs and provisions leave earnings and returns on equity resilient. IDX’s index figures do not say whether foreign investors sold BBRI shares.
Watch funding costs and margins
BMRI fell 4.23% and took 14.68 points off the IHSG. A stronger case would need stable low-cost deposits, lending margins and credit costs, along with a wider market recovery. A lower share price alone does not prove the stock is cheap.
The price changes and IHSG point contributions come from IDX. The business questions above are things to check. This report does not claim a current earnings result, a valuation multiple, foreign selling in any one stock or a confirmed company catalyst.
05 OUTLOOK
What would make a recovery more convincing
Watch 6,200 as a nearby round number and 6,300 as the first sign of recovery. Wednesday’s 6,374.912 close is a tougher test. These levels have not been tested as support or resistance. The 6,374.912 figure is a closing price, not the highest price reached during that day.
| Index level | Required move | Basis |
|---|
How far are those levels?
Required move = (reference level ÷ 6,241.892 − 1) × 100. A negative result shows a fall to the level. A positive result shows how much the index would need to rise.
What to watch from 28 September to 2 October
Watch whether trading crowds into the closing auction and whether foreign selling continues into October. Portfolio rebalancing is one possibility, not a confirmed reason for the trades.
Watch how banks put the inclusive-financing rules into practice. BI gave 1 October as the start date. That does not show an immediate benefit to bank earnings.
BI’s Indonesian calendar places this release in the week of 27 September to 3 October. Watch headline and core inflation for clues about price pressure and room for a rate change. This report could not confirm the exact day or time.
BI’s Indonesian and English calendars did not match on some other entries. This report no longer gives dates for broad money or the international investment position. Check BI’s latest calendar before acting on a release.
Stay cautious and add exposure in stages. Wait for more sectors to join a recovery and for daily foreign selling to ease. If you measure returns in dollars without a hedge, check the currency cost against a rate you could actually trade at. A lower index level alone does not make shares good value.
06 SOURCES AND METHOD
Where the numbers come from
Figures checked on 26 September 2026. The charts show their main calculations beside them. Choose the report for the right date on each source site below.
- Market trading: IDX Statistics archive. Choose the Weekly reports for 11, 18 and 25 September 2026, and the Daily reports for 18 and 21 to 25 September. The 25 September Weekly report has market activity and foreign net buying on pages 1 and 2, trading by venue on page 4, index movers on page 5 and sector returns on page 7. The Daily reports have the closing levels and net foreign buying on pages 1 and 2.
- Currency and rates: BI JISDOR for 18 to 25 September, BI’s explanation of JISDOR, BI’s September policy statement and the Fed’s 16 September statement.
- Investor classification: IDX’s explanation of how it records foreign and domestic investors.
- Upcoming releases: BI’s Indonesian publication calendar. The calendar may change after this review.
All returns are price returns. Rp bn means billions of rupiah and Rp tn means trillions. IDX marks trades as foreign or domestic using the domicile recorded in its trading system. That does not always tell us who ultimately owns the shares. The reports show trading value by market, but do not split foreign net buying by market. This report does not put odds on its scenarios.