diff --git a/pyproject.toml b/pyproject.toml
index fac8544..65930ef 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,6 +16,7 @@ dependencies = [
     "pydantic-settings>=2.0.0",
     "python-jose[cryptography]>=3.3.0",
     "passlib[bcrypt]>=1.7.4",
+    "bcrypt<=4.0.1",
     "apscheduler>=3.10.0",
     "httpx>=0.27.0",
     "alpaca-py>=0.30.0",