BIST 100 to 11,577.12 under a still-tight real rate

BIST 100 reaches 11,577.12 by November 12, 2026 in the base case, 11,947.18 in the bull case and 10,707.18 in the bear case. The base case repairs the post-decision slide, back to the October 21 close, if the Central Bank of the Republic of Türkiye (TCMB) leaves the real-rate cushion intact at the Inflation Report.

The one-week repo stands at 36 percent after a cut of 100 basis points on October 22, 2026, and September consumer prices were 29.73 percent above a year earlier, a gap of 6.27 percentage points. Borsa İstanbul 100 (BIST 100) closed the last full session on October 27 at 11,151.03, down 5.48 percent over five sessions. What follows fixes the levels, reads that tape against the inflation print, and sets the four observations that would end a repair to the October 21 close.

Key Levels:

• Asset: BIST 100 (XU100) at 11,151.03, the October 27, 2026 close — MarketScreener. October 28 is a half day and October 29 is closed (Borsa İstanbul holidays).
• Base case target: 11,577.12 by November 12, 2026 — the October 21 close, 3.82 percent above spot.
• Bull case target: 11,947.18 if the Inflation Report lowers the path — the September 30 close, 7.14 percent higher.
• Bear case target: 10,707.18 if the report lifts the path — the October 23 low, 3.98 percent under spot.
• Major support: 10,707.18 — the October 23 session low.
• Major resistance: 11,577.12 — the October 21 close.
• Invalidation level: a daily close below 10,373.75 — the 52-week low on MarketWatch as of October 27.

How the levels, the calendar and the sources were set

The horizon is the next Inflation Report on the TCMB calendar, November 12, 2026, beside the October 22 decision, the October 30 summary and the November 27 Financial Stability Report. The next rate decision is December 10, 2026. November 12 can reset the disinflation path used then, while October 30 only summarises a decision already published. Rates come from TCMB decision 2026-45. Prices come from the Presidency of Strategy and Budget note of October 5, 2026 on the Turkish Statistical Institute (TÜİK) release: annual inflation 29.73 percent, monthly inflation 1.84 percent, and core inflation of 28.70 percent. The series is a delayed lira price index.

Related:OMXS30 fades to 3,162.78 under the Riksbank rate path

What the October tape and the September inflation print show

The ex-post real policy gap on BIST 100 is the one-week repo auction rate minus annual consumer-price inflation. TCMB set that repo rate at 36 percent on October 22, 2026, down 100 basis points from 37 percent, and the Presidency of Strategy and Budget put September consumer prices 29.73 percent above a year earlier after a monthly rise of 1.84 percent. The gap is 6.27 percentage points, and versus core inflation of 28.70 percent it is 7.30 points. The index those rates discount, BIST 100, closed October 27 at 11,151.03, down 5.48 percent over five sessions, with the decision day itself ending at 11,220.37, a fall of 3.08 percent from the October 21 close of 11,577.12. The base case uses 11,577.12 as the repair level if the November 12 Inflation Report leaves the disinflation path intact, with producer energy prices up 30.82 percent on the year as the cost channel that can close the gap.

Sources: MarketScreener delayed Borsa İstanbul quote, October 27, 2026; TCMB decision 2026-45; Presidency of Strategy and Budget, September prices, October 5, 2026. Window: September inflation and closes from October 21 through October 27.

"Disinflation has been delayed, but we believe not derailed."

— Karen Vartapetov, director and sovereign lead analyst for Central and Eastern Europe and Turkey, S&P Global (Reuters)

He tied that line to weaker demand, slower retail sales and lower credit growth, the pattern tracked on the OMXS30 path under the Riksbank when a central bank eases and withholds a schedule.

Why a still-tight real rate can lift BIST 100 into the inflation report

Into November 12 the tape holds the October 30 summary, with October 29 shut and October 28 a half day.

BIST 100's repair into the November 12 Inflation Report asks whether a still-positive real policy rate can undo a decision-day drop. The benchmark closed October 27, 2026 at 11,151.03, which is 3.82 percent under the October 21 close of 11,577.12 and 7.14 percent under the September 30 close of 11,947.18. The one-week repo is 36 percent against September annual inflation of 29.73 percent, an ex-post gap of 6.27 percentage points. The base case, a return to 11,577.12, needs the Inflation Report to leave that gap intact. The bull case of 11,947.18 needs the report to mark the year-end path lower while producer energy prices, up 30.82 percent, stay outside the forecast. The bear case, the October 23 low of 10,707.18, is the print if the report lifts the path and December 10 is then read as a pause. The 52-week low of 10,373.75 sits 6.97 percent under the October 27 close and is the floor under that bear case.

The opposing reading treats 11,577.12 as supply, because the cut withheld a schedule for the banks. The base case still looks for the repair on the 6.27-point gap. An unchanged stance is handled as a level in the Swiss Market Index hold case, the TOPIX policy-guideline case and the BEL 20 rate-path case.

Where the real-rate framework fails

The 6.27-point gap uses realised prices. Adem Ileri and Seda Guler Mert of BBVA Research cite year-end inflation expectations of 29.6 percent and end-2027 expectations of 23.3 percent, against one-year figures of 45.6 percent for households and 32.5 percent for the real sector. Household expectations sit above the 36 percent policy rate, so the cushion is thinner than the ex-post gap, which is why the bull case stops at the September 30 close. Reuters reported that Vartapetov framed investment-fund stresses as a supervision issue, separate from a wider stability threat, and that shock can still lift the equity risk premium.

"With inflation likely to remain sticky at around 30% until late 1Q27, we forecast the policy rate to remain at 36% until clearer signs of disinflation emerge."

— Adem Ileri, principal economist for Türkiye, and Seda Guler Mert, chief economist for Türkiye, BBVA Research (BBVA Research)

What would invalidate this path

The base case to 11,577.12 breaks if any one of these four signals prints.

• The November 12 Inflation Report lifts the end-2026 path above 30 percent. The latest annual print is 29.73 percent and BBVA's year-end forecast sits at 30 percent. A higher path compresses the 6.27-point gap and gives December 10 a reason to pause.
• The October 30 summary pre-commits to a hold at 36 percent. The decision left size and timing open. A pre-commitment removes the December option and turns 11,577.12 into supply.
• A daily close under the October 23 low of 10,707.18 before November 12. That low is the post-decision washout. A close beneath it means the repair failed with the catalyst still ahead.
• A daily close under the 52-week low of 10,373.75. That level, 6.97 percent under the October 27 close, is the invalidation. Below it the range that holds every target here is gone.

What the calendar puts on the tape next

October 30, 2026 is the meeting summary, and equities reopen fully that day after the half day and Republic Day. November 12 is the Inflation Report and the horizon for 11,577.12. November 27 brings the Financial Stability Report, and December 10 is the next Monetary Policy Committee decision. BBVA says a further cut of 100 basis points is available if year-end inflation looks likely to finish under 30 percent, and otherwise looks for a hold at 36 percent.

TL;DR

BIST 100 closed October 27, 2026 at 11,151.03, down 5.48 percent over five sessions, after TCMB cut the one-week repo by 100 basis points to 36 percent. September annual inflation was 29.73 percent, so the ex-post gap is 6.27 percentage points. The base case returns to the October 21 close of 11,577.12 by the November 12 Inflation Report. The bull case is 11,947.18 if that report lowers the path, and the bear case is 10,707.18 if it lifts the path. A daily close under 10,373.75 ends the framework.

FAQ

What is the BIST 100 base-case level, and by when?

The base case is 11,577.12, the October 21, 2026 close, by the November 12 Inflation Report. From the October 27 close of 11,151.03 the move is 3.82 percent, repairing the slide through 11,220.37 on the decision day. The bull case at 11,947.18 and the bear case at 10,707.18 bracket that repair if the report changes the path inherited by the December 10 meeting.

Why did BIST 100 fall on the day of a rate cut?

The repo was cut from 37 percent to 36 percent on October 22, 2026, and the overnight corridor moved by 100 basis points to 34.5 percent and 39 percent. BIST 100 still fell 3.08 percent, from 11,577.12 to 11,220.37. The decision kept the stance tight until price stability and left further steps to a meeting-by-meeting reading. A cut that withholds a schedule differs from one that promises several more.

How wide is the real-rate gap the thesis uses?

The ex-post gap is 6.27 percentage points, a 36 percent repo minus September annual inflation of 29.73 percent. Versus core inflation of 28.70 percent the gap is 7.30 points. Realised prices flatter the stance relative to household one-year expectations, which BBVA Research cites at 45.6 percent, and that survey gap is why the bull case stops at the September month-end.

What would end the base case before the inflation report?

A path above 30 percent would compress the 6.27-point cushion. An October 30 summary that pre-commits to holding 36 percent would remove the December 10 option. A daily close under 10,707.18 would mean the repair failed with the catalyst still ahead, and a close under 10,373.75 would break the range around all three targets.

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