diff --git a/litellm/cost_calculator.py b/litellm/cost_calculator.py
index ee102e82ca4..6561adc2f89 100644
--- a/litellm/cost_calculator.py
+++ b/litellm/cost_calculator.py
@@ -920,7 +920,7 @@ def _declares_rates(model_info: ModelInfo | None) -> bool:
     return model_info is not None and cost_map_key_prices_anything(model_info["key"])
 
 
-def _base_model_pricing_provider(base_model: str, custom_llm_provider: str | None) -> str | None:
+def base_model_pricing_provider(base_model: str, custom_llm_provider: str | None) -> str | None:
     """The provider to price an explicit base_model under, when the deployment's own provider has
     no rates for it (e.g. chatgpt/ subscription rows) but the base model's own row does"""
     if custom_llm_provider is None or _declares_rates(_cost_map_model_info(base_model, custom_llm_provider)):
@@ -1702,7 +1702,7 @@ def completion_cost(
             _configured_search_cost_per_query(litellm_logging_obj) if custom_pricing else None
         )
         base_model_provider: Final = (
-            _base_model_pricing_provider(
+            base_model_pricing_provider(
                 base_model,
                 _get_provider_for_cost_calc(
                     model=model,
diff --git a/litellm/litellm_core_utils/litellm_logging.py b/litellm/litellm_core_utils/litellm_logging.py
index 26949d9bbfb..24c0bc3e785 100644
--- a/litellm/litellm_core_utils/litellm_logging.py
+++ b/litellm/litellm_core_utils/litellm_logging.py
@@ -52,6 +52,7 @@ from litellm.constants import (
 from litellm.cost_calculator import (
     RealtimeAPITokenUsageProcessor,
     ResponsesWebSocketTokenUsageProcessor,
+    base_model_pricing_provider,
     get_usage_object,
     pricing_entry_for_cost_calc,
     select_model_name_for_cost_calc,
@@ -6895,10 +6896,20 @@ class StandardLoggingPayloadSetup:
         if model_cost_name is None:
             model_cost_information = StandardLoggingModelInformation(model_map_key="", model_map_value=None)
         else:
+            # When base_model points at a priced row under a different provider than the deployment's own
+            # transport (e.g. a chatgpt/ subscription deployment priced via an openai/ base_model), completion_cost
+            # already resolves the correct provider for billing. Without the same correction here, get_model_info
+            # rejects the match on provider mismatch and this diagnostic field stays None even though spend is
+            # computed correctly.
+            pricing_provider: Final = (
+                base_model_pricing_provider(base_model, custom_llm_provider)
+                if base_model is not None and custom_pricing is not True
+                else None
+            )
             try:
                 _model_cost_information: Final = litellm.get_model_info(
                     model=pricing_model_name or model_cost_name,
-                    custom_llm_provider=custom_llm_provider,
+                    custom_llm_provider=pricing_provider or custom_llm_provider,
                     api_base=api_base,
                 )
                 model_cost_information = StandardLoggingModelInformation(
diff --git a/tests/unit/litellm_core_utils/test_litellm_logging.py b/tests/unit/litellm_core_utils/test_litellm_logging.py
index f7c2082b683..eaddb3993ad 100644
--- a/tests/unit/litellm_core_utils/test_litellm_logging.py
+++ b/tests/unit/litellm_core_utils/test_litellm_logging.py
@@ -12506,6 +12506,32 @@ def test_get_model_cost_information_keeps_a_priced_response_model_that_echoes_wi
     assert result["model_map_value"]["input_cost_per_token"] == served_row["input_cost_per_token"]
 
 
+@pytest.mark.usefixtures("_vcr_outcome_gate", "drain_logging_worker", "isolate_litellm_state", "setup_and_teardown")
+def test_get_model_cost_information_base_model_cross_provider():
+    """Regression test for #47908: a deployment whose transport provider differs from the priced
+    base_model's own registered provider must still populate model_map_value, not just completion_cost's
+    return value, since the two used to disagree (spend computed correctly, this field stayed None)."""
+    litellm.register_model(
+        model_cost={
+            "custom-provider/base-model-cross-provider-test": {
+                "input_cost_per_token": 1.5e-07,
+                "output_cost_per_token": 5e-07,
+                "litellm_provider": "custom-provider",
+                "mode": "chat",
+            }
+        }
+    )
+
+    result = StandardLoggingPayloadSetup.get_model_cost_information(
+        base_model="custom-provider/base-model-cross-provider-test",
+        custom_pricing=False,
+        custom_llm_provider="openai",
+        init_response_obj={},
+    )
+    assert result["model_map_value"] is not None
+    assert result["model_map_value"]["input_cost_per_token"] == 1.5e-07
+    assert result["model_map_value"]["litellm_provider"] == "custom-provider"
+
 @pytest.mark.usefixtures("_vcr_outcome_gate", "drain_logging_worker", "isolate_litellm_state", "setup_and_teardown")
 def test_standard_logging_payload_uses_deployment_when_no_base_model():
     """metadata["deployment"] is used for cost-map lookup when base_model is not set."""