diff --git a/prediction_market_agent_tooling/markets/omen/omen_subgraph_handler.py b/prediction_market_agent_tooling/markets/omen/omen_subgraph_handler.py
index 53752d4d..c88a25b4 100644
--- a/prediction_market_agent_tooling/markets/omen/omen_subgraph_handler.py
+++ b/prediction_market_agent_tooling/markets/omen/omen_subgraph_handler.py
@@ -383,7 +383,9 @@ def _parse_items_from_json(
         for result_chunk in result:
             for k, v in result_chunk.items():
                 # subgrounds might pack all items as a list, indexed by a key, or pack it as a dictionary (if one single element)
-                if isinstance(v, dict):
+                if v is None:
+                    continue
+                elif isinstance(v, dict):
                     items.extend([v])
                 else:
                     items.extend(v)
diff --git a/pyproject.toml b/pyproject.toml
index bfa767ba..9813b040 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "prediction-market-agent-tooling"
-version = "0.39.2"
+version = "0.39.3"
 description = "Tools to benchmark, deploy and monitor prediction market agents."
 authors = ["Gnosis"]
 readme = "README.md"
diff --git a/tests/markets/omen/test_omen_subgraph_handler.py b/tests/markets/omen/test_omen_subgraph_handler.py
index 9f41dd66..ee5e3dcc 100644
--- a/tests/markets/omen/test_omen_subgraph_handler.py
+++ b/tests/markets/omen/test_omen_subgraph_handler.py
@@ -279,3 +279,9 @@ def test_get_markets_id_in() -> None:
     )
     assert len(markets) == 1
     assert markets[0].id == market_id
+
+
+def test_omen_get_non_existing_market_by_id() -> None:
+    with pytest.raises(ValueError) as e:
+        OmenSubgraphHandler().get_omen_market_by_market_id(HexAddress(HexStr("0x123")))
+    assert "Fetched wrong number of markets. Expected 1 but got 0" in str(e)