diff --git a/sdks/python/pmxt/models.py b/sdks/python/pmxt/models.py
index 31046e6b..a4ce932d 100644
--- a/sdks/python/pmxt/models.py
+++ b/sdks/python/pmxt/models.py
@@ -310,6 +310,9 @@ class OrderLevel:
     size: float
     """Number of contracts"""
 
+    order_count: Optional[int] = None
+    """Number of orders aggregated at this price level, when reported by the venue."""
+
 
 @dataclass
 class OrderBook:
@@ -327,6 +330,15 @@ class OrderBook:
     datetime: Optional[str] = None
     """ISO 8601 datetime string (CCXT-compatible)"""
 
+    is_neg_risk: Optional[bool] = None
+    """Whether the underlying market uses negative-risk collateral/netting semantics."""
+
+    last_trade_price: Optional[float] = None
+    """Last traded price for the outcome, when reported alongside the book."""
+
+    source_metadata: Optional[Dict[str, Any]] = None
+    """Raw venue-specific fields not promoted to first-class columns."""
+
 
 @dataclass
 class FirehoseEvent:
diff --git a/sdks/typescript/pmxt/models.ts b/sdks/typescript/pmxt/models.ts
index 43510bce..78e845e7 100644
--- a/sdks/typescript/pmxt/models.ts
+++ b/sdks/typescript/pmxt/models.ts
@@ -149,6 +149,9 @@ export interface OrderLevel {
 
     /** Number of contracts */
     size: number;
+
+    /** Number of orders aggregated at this price level, when reported by the venue. */
+    orderCount?: number;
 }
 
 /**
@@ -166,6 +169,15 @@ export interface OrderBook {
 
     /** ISO 8601 datetime string of the snapshot (CCXT-compatible) */
     datetime?: string;
+
+    /** Whether the underlying market uses negative-risk collateral/netting semantics. */
+    isNegRisk?: boolean;
+
+    /** Last traded price for the outcome, when reported alongside the book. */
+    lastTradePrice?: number;
+
+    /** Raw venue-specific fields not promoted to first-class columns. */
+    sourceMetadata?: Record<string, unknown>;
 }
 
 /**