diff --git a/application/runtime_broker_adapters.py b/application/runtime_broker_adapters.py
index 466287d..6b05d59 100644
--- a/application/runtime_broker_adapters.py
+++ b/application/runtime_broker_adapters.py
@@ -112,6 +112,11 @@ def is_read_only_error(message: Any) -> bool:
             normalized = str(message).lower().replace("-", " ").replace("_", " ")
             return "read only" in " ".join(normalized.split())
 
+        def is_margin_probe_rejection(message: Any) -> bool:
+            """Margin rejection still proves the API accepted a non-transmitting order."""
+            normalized = str(message).upper()
+            return "INITIAL MARGIN" in normalized or "EQUITY WITH LOAN VALUE" in normalized
+
         def capture_api_error(_request_id, error_code, error_message, _contract):
             if is_read_only_error(error_message):
                 read_only_errors.append((error_code, str(error_message)))
@@ -146,6 +151,9 @@ def capture_api_error(_request_id, error_code, error_message, _contract):
                 raise IBKRTradingPermissionError(
                     "IB Gateway API is in Read-Only mode; live execution is disabled."
                 ) from exc
+            if is_margin_probe_rejection(exc):
+                # Write path reached the broker; small accounts may reject the probe size.
+                return
             raise IBKRTradingPermissionError(
                 "IB Gateway live execution could not verify non-transmitting order-write access "
                 f"(error_type={type(exc).__name__})."
diff --git a/main.py b/main.py
index a5a1e42..219dec5 100644
--- a/main.py
+++ b/main.py
@@ -695,6 +695,14 @@ def compute_signals_fn(ib, current_holdings):
             )
         return compute_signals(ib, current_holdings)
 
+    def connect_ib_for_cycle():
+        # Dry-run/shadow must use a read-only Gateway session and must not run the
+        # live what-if write probe (that path can emit Error 201 on small accounts).
+        return connect_ib(
+            read_only=bool(effective_dry_run_only),
+            validate_trading_permissions=not bool(effective_dry_run_only),
+        )
+
     return build_runtime_composer(
         service_name=SERVICE_NAME or os.getenv("K_SERVICE", "interactive-brokers-platform"),
         strategy_profile=STRATEGY_PROFILE,
@@ -728,7 +736,7 @@ def compute_signals_fn(ib, current_holdings):
         separator=SEPARATOR,
         send_message=send_tg_message,
         notification_channel=_NOTIFICATION_CHANNEL,
-        connect_ib_fn=connect_ib,
+        connect_ib_fn=connect_ib_for_cycle,
         build_portfolio_snapshot_fn=build_portfolio_snapshot,
         compute_signals_fn=compute_signals_fn,
         execute_rebalance_fn=lambda ib, target_weights, positions, account_values, **kwargs: execute_rebalance(
diff --git a/tests/test_request_handling.py b/tests/test_request_handling.py
index 68879b1..e9f2d56 100644
--- a/tests/test_request_handling.py
+++ b/tests/test_request_handling.py
@@ -409,6 +409,24 @@ def fake_build_broker_adapters(*, dry_run_only_override=None):
     assert observed["dry_run_only_override"] is True
 
 
+def test_dry_run_composer_connects_read_only_without_permission_probe(
+    strategy_module, monkeypatch
+):
+    observed = {}
+
+    def fake_connect_ib(*, read_only=False, validate_trading_permissions=True):
+        observed["read_only"] = read_only
+        observed["validate_trading_permissions"] = validate_trading_permissions
+        return object()
+
+    monkeypatch.setattr(strategy_module, "connect_ib", fake_connect_ib)
+
+    runtime = strategy_module.build_composer(dry_run_only_override=True).build_rebalance_runtime()
+    runtime.connect_ib()
+
+    assert observed == {"read_only": True, "validate_trading_permissions": False}
+
+
 def test_probe_market_order_write_access_uses_safe_haven_not_growth_symbol(
     strategy_module, monkeypatch
 ):
@@ -1268,8 +1286,14 @@ def isConnected(self):
         def disconnect(self):
             observed["disconnect_calls"] += 1
 
-    def fake_connect_ib():
+    def fake_connect_ib(*, read_only=False, validate_trading_permissions=True):
         observed["connect_calls"] += 1
+        observed.setdefault("connection_options", []).append(
+            {
+                "read_only": read_only,
+                "validate_trading_permissions": validate_trading_permissions,
+            }
+        )
         return FakeIB()
 
     monkeypatch.setattr(strategy_module, "connect_ib", fake_connect_ib)
diff --git a/tests/test_runtime_broker_adapters.py b/tests/test_runtime_broker_adapters.py
index 525d66e..a759a76 100644
--- a/tests/test_runtime_broker_adapters.py
+++ b/tests/test_runtime_broker_adapters.py
@@ -225,6 +225,42 @@ def disconnect(self):
     }
 
 
+def test_connect_ib_accepts_margin_rejection_as_write_access_proof():
+    class FakeEvent:
+        def __iadd__(self, handler):
+            return self
+
+        def __isub__(self, handler):
+            return self
+
+    class FakeIB:
+        RaiseRequestErrors = False
+        RequestTimeout = 0
+
+        def __init__(self):
+            self.errorEvent = FakeEvent()
+
+        def managedAccounts(self):
+            return ["U1234567"]
+
+        def whatIfOrder(self, _contract, _order):
+            raise RuntimeError(
+                "Error 201, reqId 21: Order rejected - reason:YOUR ORDER IS NOT ACCEPTED. "
+                "IN ORDER TO OBTAIN THE DESIRED POSITION YOUR EQUITY WITH LOAN VALUE "
+                "[390.06 USD] MUST EXCEED THE INITIAL MARGIN [434.70 USD]"
+            )
+
+    adapters = _build_adapters(account_ids=("U1234567",), execution_mode="live")
+    adapters = adapters.__class__(
+        **{
+            **adapters.__dict__,
+            "connect_ib_fn": lambda *_args, **_kwargs: FakeIB(),
+        }
+    )
+
+    assert adapters.connect_ib().managedAccounts() == ["U1234567"]
+
+
 def test_connect_ib_retries_when_trading_permission_probe_loses_connection():
     observed = {
         "connects": 0,