diff --git a/amaascore/transactions/mtm_result.py b/amaascore/transactions/mtm_result.py
index <HASH>..<HASH> 100644
--- a/amaascore/transactions/mtm_result.py
+++ b/amaascore/transactions/mtm_result.py
@@ -55,7 +55,7 @@ class MTMResult(AMaaSModel):
 
     @mtm_value.setter
     def mtm_value(self, val):
-        if not isinstance(val, Decimal):
+        if not isinstance(val, Decimal) and val is not None:
             self._mtm_value = Decimal(val)
         else:
             self._mtm_value = val
\ No newline at end of file
diff --git a/setup.py b/setup.py
index <HASH>..<HASH> 100644
--- a/setup.py
+++ b/setup.py
@@ -11,7 +11,7 @@ requires = [
 
 setup(
     name='amaascore',
-    version='0.5.18',
+    version='0.5.19',
     description='Asset Management as a Service - Core SDK',
     license='Apache License 2.0',
     url='https://github.com/amaas-fintech/amaas-core-sdk-python',
made mtm_value nullable