diff --git a/seismostats/analysis/estimate_beta.py b/seismostats/analysis/estimate_beta.py
index 19223af..93161b7 100644
--- a/seismostats/analysis/estimate_beta.py
+++ b/seismostats/analysis/estimate_beta.py
@@ -300,7 +300,7 @@ def estimate_b_positive(
 
     out = estimate_b_tinti(
         mag_diffs,
-        mc=delta_m,
+        mc=d_mc,
         delta_m=delta_m,
         b_parameter=b_parameter,
         return_std=return_std,