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Build a 10‑Year Fixed Mortgage Forecast from Bundesbank Pfandbrief and Bund Yields (snapshot 18 Sep 2026)
Step‑by‑step guide showing the official Bundesbank Pfandbrief data and the Bundesanleihe (Bund) yield (snapshot 18 Sep 2026), exact source URLs, and precise Excel steps to produce a 10‑year fixed‑rate mortgage forecast.
What you need and where to get it
Two official data items are required for this method: the Bundesbank’s derived Pfandbrief yields by residual maturity (you will use the 10‑year residual‑maturity series) and the market yield on the 10‑year German federal bond (Bund) for the same date. The Bundesbank publishes a daily term‑structure file and downloadable CSV series for Pfandbriefe, including a series labelled “Yields, derived from the term structure of interest rates, on Pfandbriefe … residual maturity 10.0 years” (daily). Use the Bundesbank page titled “Daily term structure on Pfandbriefe” to access the PDF and the CSV links. ([bundesbank.de](https://www.bundesbank.de/en/statistics/money-and-capital-markets/interest-rates-and-yields/daily-term-structure-on-pfandbriefe-651580))
Confirmed snapshot: Bund 10‑year yield on 18 Sep 2026
For the 18 September 2026 snapshot you can read the 10‑year Bund yield on the German Finance Agency pages (Bundesanleihe factsheets / front page market data). The Deutsche Finanzagentur lists the “Bundesanleihe 10 Jahre” quote for 18.09.2026; use that figure as the market reference in your model. For example (as reported on the agency page), the 10‑year Bund yield on 18.09.2026 is 3.50 %. Always cite the exact factsheet or the agency front page row you used. ([deutsche-finanzagentur.de](https://www.deutsche-finanzagentur.de/?utm_source=openai))
Exact Bundesbank download steps (Pfandbrief 10y, date 18.09.2026)
1) Open the Bundesbank page “Daily term structure on Pfandbriefe”. On that page click the PDF for the date 18.09.2026 to review the snapshot table. 2) On the same page use the direct CSV link labelled for the series “Yields, derived from the term structure … residual maturity 10.0 years / daily data”. The CSV is the machine‑readable source you will import into Excel. 3) Note the CSV column layout: date (ISO: yyyy‑mm‑dd) and yield (percent). Save the CSV to your drive. ([bundesbank.de](https://www.bundesbank.de/en/statistics/money-and-capital-markets/interest-rates-and-yields/daily-term-structure-on-pfandbriefe-651580))
Excel import and cleaning — exact steps
1) In Excel (modern Office) use Data > Get Data > From File > From Text/CSV and pick the saved CSV. Set the locale to English (or German) so Excel recognises the decimal separator in the file. 2) In Power Query: ensure the date column is Date type and the yield column is Decimal Number (percentage). Rename the yield column Pfand_10y. Load to a worksheet. 3) On a second sheet enter the Bund 10‑y yield you obtained from the Deutsche Finanzagentur (cell B2). Record the snapshot date explicitly (cell B1 = 2026‑09‑18). This ties the Bund quote to the same date as your Pfandbrief row. ([bundesbank.de](https://www.bundesbank.de/en/statistics/money-and-capital-markets/interest-rates-and-yields/daily-term-structure-on-pfandbriefe-651580))
Model: convert yields to a mortgage offer forecast (Excel formulas)
A transparent, reproducible model keeps three inputs variable: Pfand_10y (from the Bundesbank CSV for 2026‑09‑18), Bund_10y (from Deutsche Finanzagentur, e.g. 3.50 % on 18.09.2026), and Bank_Margin (your chosen lender spread, entered as decimal). Suggested cell layout: Sheet1!A1 = Snapshot date (2026‑09‑18); A2 = Pfand_10y (linked via XLOOKUP: =XLOOKUP(A1, PfandTable[Date], PfandTable[Yield])) ; A3 = Bund_10y (manual or linked) ; A4 = Bank_Margin (input). Forecast formula (cell A5): =A2 + A4 — i.e. Forecasted_10y_mortgage_rate = Pfand_10y + Bank_Margin. Use XLOOKUP or INDEX/MATCH to pull the exact Pfand_10y for 2026‑09‑18. ([bundesbank.de](https://www.bundesbank.de/en/statistics/money-and-capital-markets/interest-rates-and-yields/daily-term-structure-on-pfandbriefe-651580))
Monthly payments and sensitivity
Once you have Forecasted_10y_rate in decimal (e.g. cell A5), compute monthly payment for a loan amount L, term 10 years (n = 120 months) using Excel’s PMT: =PMT(A5/12, 120, -L). Put L as a separate input cell so readers can change loan size. Add a sensitivity table (Data Table or two‑way table) that varies Bank_Margin ±0.5 percentage points and Pfand_10y ±0.25 % to show how payments change. Label every table column and keep snapshot date visible so the forecast is auditable. ([bundesbank.de](https://www.bundesbank.de/en/statistics/money-and-capital-markets/interest-rates-and-yields/daily-term-structure-on-pfandbriefe-651580))
Assumptions, limitations and next steps
This approach uses market reference yields only. Actual bank offers include credit assessment, borrower‑specific pricing, fees, and prepayment terms; those items are not in the Bundesbank/Finanzagentur data. Do not treat the model’s result as a binding quote. For an executed purchase or investment, ask a mortgage broker or the lender for a written offer and compare with the model. If you need the Pfandbrief 10‑year numeric value for 18.09.2026 pulled into the workbook as a concrete number, import the Bundesbank CSV and use the XLOOKUP step above to extract that exact cell (do not type it manually). ([bundesbank.de](https://www.bundesbank.de/en/statistics/money-and-capital-markets/interest-rates-and-yields/daily-term-structure-on-pfandbriefe-651580))
Nothing on this page is investment, tax or legal advice. Price bands are indicative asking prices and disagree between sources by design. Verify every figure with a qualified German notary, tax adviser (Steuerberater) or lawyer before committing capital.
