diff --git a/src/cerbero_mcp/exchanges/ibkr/orders_complex.py b/src/cerbero_mcp/exchanges/ibkr/orders_complex.py
new file mode 100644
index 0000000..3ba9109
--- /dev/null
+++ b/src/cerbero_mcp/exchanges/ibkr/orders_complex.py
@@ -0,0 +1,101 @@
+"""Pure-function payload builders for IBKR complex orders (bracket/OCO/OTO).
+
+No HTTP. Tests are deterministic.
+"""
+from __future__ import annotations
+
+import secrets
+from dataclasses import dataclass
+from typing import Literal
+
+
+@dataclass
+class OrderSpec:
+    conid: int
+    sec_type: str  # "STK" | "OPT" | "FUT" | "CASH"
+    side: Literal["BUY", "SELL"]
+    qty: float
+    order_type: Literal["MKT", "LMT", "STP", "STP_LMT"]
+    price: float | None = None      # limit price
+    aux_price: float | None = None  # stop price
+    tif: str = "GTC"
+    exchange: str = "SMART"
+
+
+def _to_order_dict(spec: OrderSpec, *, oca_group: str | None = None,
+                   oca_type: int | None = None,
+                   parent_id: str | None = None) -> dict:
+    o: dict = {
+        "conid": spec.conid,
+        "secType": f"{spec.conid}:{spec.sec_type}",
+        "orderType": spec.order_type,
+        "side": spec.side,
+        "quantity": spec.qty,
+        "tif": spec.tif,
+        "listingExchange": spec.exchange,
+    }
+    if spec.price is not None:
+        o["price"] = spec.price
+    if spec.aux_price is not None:
+        o["auxPrice"] = spec.aux_price
+    if oca_group:
+        o["ocaGroup"] = oca_group
+    if oca_type is not None:
+        o["ocaType"] = oca_type
+    if parent_id:
+        o["parentId"] = parent_id
+    return o
+
+
+def _new_oca_group() -> str:
+    return f"oca-{secrets.token_hex(4)}"
+
+
+def build_bracket_payload(
+    *, conid: int, sec_type: str, side: str, qty: float,
+    entry_price: float, stop_loss: float, take_profit: float,
+    tif: str = "GTC", exchange: str = "SMART",
+) -> dict:
+    """Bracket: parent LMT entry + child STP (loss) + child LMT (profit), OCA-linked."""
+    side = side.upper()
+    opposite = "SELL" if side == "BUY" else "BUY"
+    oca = _new_oca_group()
+
+    parent = OrderSpec(conid=conid, sec_type=sec_type, side=side, qty=qty,  # type: ignore[arg-type]
+                       order_type="LMT", price=entry_price,
+                       tif=tif, exchange=exchange)
+    sl = OrderSpec(conid=conid, sec_type=sec_type, side=opposite, qty=qty,  # type: ignore[arg-type]
+                   order_type="STP", aux_price=stop_loss,
+                   tif=tif, exchange=exchange)
+    tp = OrderSpec(conid=conid, sec_type=sec_type, side=opposite, qty=qty,  # type: ignore[arg-type]
+                   order_type="LMT", price=take_profit,
+                   tif=tif, exchange=exchange)
+    return {
+        "orders": [
+            _to_order_dict(parent, oca_group=oca, oca_type=2),
+            _to_order_dict(sl, oca_group=oca, oca_type=2),
+            _to_order_dict(tp, oca_group=oca, oca_type=2),
+        ]
+    }
+
+
+def build_oco_payload(legs: list[OrderSpec]) -> dict:
+    """OCO: N legs, all sharing same ocaGroup with ocaType=1 (one-cancels-all)."""
+    if len(legs) < 2:
+        raise ValueError("OCO requires at least 2 legs")
+    oca = _new_oca_group()
+    return {
+        "orders": [
+            _to_order_dict(l, oca_group=oca, oca_type=1) for l in legs
+        ]
+    }
+
+
+def build_oto_first_payload(trigger: OrderSpec) -> dict:
+    """OTO step 1: place trigger as standalone."""
+    return {"orders": [_to_order_dict(trigger)]}
+
+
+def build_oto_child_payload(child: OrderSpec, parent_order_id: str) -> dict:
+    """OTO step 2: child references parentId from step-1 order_id."""
+    return {"orders": [_to_order_dict(child, parent_id=parent_order_id)]}
diff --git a/tests/unit/exchanges/ibkr/test_orders_complex.py b/tests/unit/exchanges/ibkr/test_orders_complex.py
new file mode 100644
index 0000000..56c26f2
--- /dev/null
+++ b/tests/unit/exchanges/ibkr/test_orders_complex.py
@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from cerbero_mcp.exchanges.ibkr.orders_complex import (
+    OrderSpec,
+    build_bracket_payload,
+    build_oco_payload,
+)
+
+
+def test_bracket_three_legs_with_oca():
+    payload = build_bracket_payload(
+        conid=42, sec_type="STK", side="BUY", qty=10,
+        entry_price=150.0, stop_loss=145.0, take_profit=160.0,
+        tif="GTC", exchange="SMART",
+    )
+    assert "orders" in payload
+    legs = payload["orders"]
+    assert len(legs) == 3
+    oca = legs[0].get("ocaGroup")
+    assert oca and all(l.get("ocaGroup") == oca for l in legs[1:])
+    assert legs[0]["orderType"] == "LMT"
+    assert legs[0]["price"] == 150.0
+    assert legs[0]["side"] == "BUY"
+    assert legs[1]["side"] == "SELL"
+    assert legs[2]["side"] == "SELL"
+    assert legs[1]["orderType"] == "STP"
+    assert legs[1]["auxPrice"] == 145.0
+    assert legs[2]["orderType"] == "LMT"
+    assert legs[2]["price"] == 160.0
+
+
+def test_oco_oca_group_and_type():
+    legs = [
+        OrderSpec(conid=1, sec_type="STK", side="BUY", qty=1,
+                  order_type="LMT", price=100),
+        OrderSpec(conid=1, sec_type="STK", side="BUY", qty=1,
+                  order_type="LMT", price=110),
+    ]
+    payload = build_oco_payload(legs)
+    assert len(payload["orders"]) == 2
+    oca = payload["orders"][0]["ocaGroup"]
+    for o in payload["orders"]:
+        assert o["ocaGroup"] == oca
+        assert o["ocaType"] == 1