diff --git a/src/fideslang/models.py b/src/fideslang/models.py
index cc7fe9da..fb783f69 100644
--- a/src/fideslang/models.py
+++ b/src/fideslang/models.py
@@ -225,11 +225,18 @@ class LegalBasisForProfilingEnum(str, Enum):
 
 
 class LegalBasisForTransfersEnum(str, Enum):
-    """The model for describing the legal basis under which data is transferred"""
+    """
+    The model for describing the legal basis under which data is transferred
+
+    We currently do _not_ enforce this enum on the `legal_basis_for_transfers`
+    field, because the set of allowable values seems to be changing frequently
+    and without clear notice in upstream, public data sources.
+    """
 
     ADEQUACY_DECISION = "Adequacy Decision"
     SCCS = "SCCs"
     BCRS = "BCRs"
+    SUPPLEMENTARY_MEASURES = "Supplementary Measures"
     OTHER = "Other"
 
 
@@ -1181,7 +1188,7 @@ class System(FidesModel):
         default=False,
         description="Whether this system transfers data to other countries or international organizations.",
     )
-    legal_basis_for_transfers: List[LegalBasisForTransfersEnum] = Field(
+    legal_basis_for_transfers: List[str] = Field(
         default_factory=list,
         description="The legal basis (or bases) under which the data is transferred.",
     )
diff --git a/tests/fideslang/test_models.py b/tests/fideslang/test_models.py
index 4a1bf365..43924559 100644
--- a/tests/fideslang/test_models.py
+++ b/tests/fideslang/test_models.py
@@ -404,7 +404,7 @@ def test_expanded_system(self):
             uses_profiling=True,
             legal_basis_for_profiling=["Explicit consent", "Contract"],
             does_international_transfers=True,
-            legal_basis_for_transfers=["Adequacy Decision", "SCCs"],
+            legal_basis_for_transfers=["Adequacy Decision", "SCCs", "New legal basis"],
             requires_data_protection_assessments=True,
             dpa_location="www.example.com/dpa_location",
             privacy_policy="https://vdx.tv/privacy/",