Harden valuation edge cases

1 files changed, 7 insertions, 0 deletions

diff --git a/services/valuation_service.py b/services/valuation_service.py
index 6db4053..8559842 100644
--- a/services/valuation_service.py
+++ b/services/valuation_service.py
@@ -79,6 +79,13 @@ def run_dcf(
         growth_rate = historical_growth if historical_growth is not None else 0.05
 
     base_fcf = float(historical[-1])
+    if base_fcf <= 0:
+        return {
+            "error": (
+                "DCF is not meaningful with zero or negative base free cash flow. "
+                "Use comps, EV/EBITDA, or adjust the model only after underwriting a credible FCF turnaround."
+            )
+        }
 
     projected_fcfs = []
     for year in range(1, projection_years + 1):