# BK conditions satisfied in count but rank condition fails (indeterminacy)

**URL:** <https://forum.dynare.org/t/bk-conditions-satisfied-in-count-but-rank-condition-fails-indeterminacy/28321>\
**Category:** Stochastic simulations\
**Created:** [26 March 2026 14:03 UTC](https://forum.dynare.org/t/bk-conditions-satisfied-in-count-but-rank-condition-fails-indeterminacy/28321 "2026-03-26T14:03:24Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![JackW](https://forum.dynare.org/letter_avatar_proxy/v4/letter/j/67e7ee/32.png) [@JackW](https://forum.dynare.org/u/JackW)\
**Post date:** [26 March 2026 14:03 UTC](https://forum.dynare.org/t/bk-conditions-satisfied-in-count-but-rank-condition-fails-indeterminacy/28321/1 "2026-03-26T14:03:24Z")

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Hi everyone,

I am encountering an issue with the Blanchard & Kahn conditions in Dynare and would really appreciate your help.

From the model output, I obtain:

- Number of eigenvalues with modulus greater than 1: **6**

- Number of forward-looking variables: **6**

However, Dynare reports:

> _Blanchard & Kahn conditions are not satisfied: indeterminacy due to rank failure._

This is confusing to me, since the **count condition appears to be satisfied** , yet the rank condition fails.

Below are the eigenvalues:

```auto
Modulus Real Imaginary
1.694e-16 1.694e-16 0
2.339e-16 2.339e-16 0
4.578e-16 -4.578e-16 0
0.1488 0.1488 0
0.2864 -0.2864 0
0.6513 0.6513 0
1.038 1.038 0
1.099 1.099 0
157.6 157.6 0
1.179e+08 -8359 1.179e+08
1.179e+08 -8359 -1.179e+08
1.03e+18 -1.03e+18 0

```

Dynare also reports:

```auto
There are 6 eigenvalue(s) larger than 1 in modulus 
for 6 forward-looking variable(s)

The rank condition ISN'T verified!

```

Additional diagnostics:

- `model_diagnostics` reports no obvious issues

- The steady state is solved using `fsolve` with small residuals

- Solver message:

My questions are:

1. Can **very large eigenvalues** (e.g. 1e+08 or 1e+18) generate numerical instability that leads to rank failure?

2. Does this typically indicate a **singularity or collinearity problem in the forward-looking block** , even if `model_diagnostics` does not detect it?

3. In general, under what conditions can the **count condition be satisfied but the rank condition still fail**?

I suspect this may be related to the structure of my model (possibly a very “stiff” static block combined with a small number of forward-looking equations), but I am not sure how to diagnose it formally.

Any suggestions on how to debug this (e.g. checking the Jacobian, identifying redundant equations, or rescaling variables) would be greatly appreciated.

Thanks a lot!

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<div class="post-metadata">

**Author:** ![jpfeifer](https://forum.dynare.org/user_avatar/forum.dynare.org/jpfeifer/32/5044_2.png) [@jpfeifer](https://forum.dynare.org/u/jpfeifer)\
**Post date:** [31 March 2026 14:36 UTC](https://forum.dynare.org/t/bk-conditions-satisfied-in-count-but-rank-condition-fails-indeterminacy/28321/2 "2026-03-31T14:36:47Z")

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Without the codes it is hard to tell. But this kind of message usually indicates a singularity. Have you tried Dynare 7 where we improved the `model_diagnostics` command?

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<div class="post-metadata">

**Author:** ![JackW](https://forum.dynare.org/letter_avatar_proxy/v4/letter/j/67e7ee/32.png) [@JackW](https://forum.dynare.org/u/JackW)\
**Post date:** [13 April 2026 08:13 UTC](https://forum.dynare.org/t/bk-conditions-satisfied-in-count-but-rank-condition-fails-indeterminacy/28321/3 "2026-04-13T08:13:25Z")

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Yeah, the model really has singularity problem. I have fixed it, thank you!