diff --git a/protocol/0019-MCAL-margin_calculator.md b/protocol/0019-MCAL-margin_calculator.md
index b0ab2ac54c..78e97802e6 100644
--- a/protocol/0019-MCAL-margin_calculator.md
+++ b/protocol/0019-MCAL-margin_calculator.md
@@ -276,7 +276,7 @@ There should be an additional amount `limit price x size x margin factor = 15910
 
   for this market the party switches to cross margin and the market has `market.linearSlippageFactor = 0.25`, `RF short = 0.1` then the maintenance margin for the party is `min(1 x (100 000-159 00), 159 00 x 0.25 x 1) + 0.1 x 1 x 159 00 = 5565`
   but if `5565 < collatoral release level` the maintenance margin will remain unchanged at `6325`
-  
+
   the difference topped up from the party’s general account(<a name="0019-MCAL-232" href="#0019-MCAL-232">0019-MCAL-232</a>)
 
 - switch to cross margin without position and no orders successful in continuous mode(<a name="0019-MCAL-134" href="#0019-MCAL-134">0019-MCAL-134</a>)
@@ -346,7 +346,11 @@ There should be an additional amount `limit price x size x margin factor = 15910
 
 **Check API:**
 
-- For each market and each party which has either orders or positions on the market, the API provides the maintenance margin levels.  (<a name="0019-MCAL-092" href="#0019-MCAL-092">0019-MCAL-092</a>)
+- For each market and each party which has positions or has switched between margin modes on the market, the API provides the maintenance margin levels. (<a name="0019-MCAL-092" href="#0019-MCAL-092">0019-MCAL-092</a>)
+
+- For each market and each party which has orders only and no positions or has switched between margin modes on the market
+  - cross margin to isolated margin, the API provides maintenance margin level of zero. (<a name="0019-MCAL-150" href="#0019-MCAL-150">0019-MCAL-150</a>)
+  - isolated margin to cross margin, the API provides expected maintenance margin level . (<a name="0019-MCAL-151" href="#0019-MCAL-151">0019-MCAL-151</a>)
 
 - For each market and each party which has either orders or positions on the market, the API provides the current margin mode and, when in isolated margin mode, margin factor.  (<a name="0019-MCAL-143" href="#0019-MCAL-143">0019-MCAL-143</a>)
 
diff --git a/protocol/features.json b/protocol/features.json
index 2c3b365291..a6885d955b 100644
--- a/protocol/features.json
+++ b/protocol/features.json
@@ -142,6 +142,8 @@
       "0019-MCAL-147",
       "0019-MCAL-148",
       "0019-MCAL-149",
+      "0019-MCAL-150",
+      "0019-MCAL-151",
       "0019-MCAL-200",
       "0019-MCAL-201",
       "0019-MCAL-202",