As of 31 December 2025, the “Referenzzins” for the calculation of the additional reserve requirement (“ZInsszusatzreserve” or “ZZR”) will again be 1.57%. With the publication of the “Bezugszins” (10-year zero-coupon euro swap rate) for September 2025 by the Bundesbank, the input values for calculating the reference interest rate are now complete.
The calculation method of the “Referenzzins” according to the publication in the Federal Law Gazette Part I of 22 October 2018 (so-called corridor method) is based on the average of the “Bezugszins” of the first nine months of the current financial year and the annual averages of the previous nine years. A comparison with the previous year’s “Referenzzins” ensures that the deviation is not too large, either upwards or downwards.
This method allows the “Referenzzins” to remain at 1.57%. If interest rates remain unchanged, this would not change before 2027. From then on, the “Referenzzins” would leave the corridor and start to rise slowly again (cf. Update on interest rates for the „Zinszusatzreserve“).
Specifically, the calculation of the “Referenzzins” (in %) for 31 December 2025 is as follows
- Value pursuant to §5 para. 3 sentence 4 DeckRV (9-month average of current year *)) =
(2.411 + 2.299 + 2.650 + 2.449 + 2.528 + 2.599 + 2.682 + 2.674 + 2.696) / 9 = 2.56 - Value according to §5 paragraph 3 sentence 5 DeckRV (average over 10 years) =
(0.51 + 0.85 + 0.96 + 0.23 – 0.19 + 0.09 + 2.02 + 3.02+ 2.57 + 2.56 ) / 10 = 1.2620. - First difference according to §5 DeckRV paragraph 3 sentence 6 (mean value minus old “Referenz-zinssatz”) = 1.2620 – 1.57 = -0.3080 rounded up to the next higher second decimal place = -0.31
- Second difference according to §5 DeckRV paragraph 3 sentence 6 = 9% * 2.56 – 9% * 1.57 = 0.0891 rounded up to the next higher second decimal place = 0.09
- The signs of the two differences are not identical, so the “Referenzzins” remains unchanged at 1.57.
*) The annual average is rounded up to two decimal places in accordance with §5(3) sentence 3 DeckRV. Here, “round up” is interpreted as “round up from zero” (cf. BaFin’s comments on the calculation of the ZZR).
Source zero-coupon euro interest rate swap rates: Deutsche Bundesbank