diff --git a/lib/nib/flex.styl b/lib/nib/flex.styl
index 4421da46..b8ca76a2 100644
--- a/lib/nib/flex.styl
+++ b/lib/nib/flex.styl
@@ -100,14 +100,17 @@ flex-grow(growth)
 
   // new
   if flex in flex-version
+    vendor('flex-positive', arguments, only: ms)
     vendor('flex-grow', arguments, only: webkit official)
 
 flex-basis()
   if flex in flex-version
+    vendor('flex-preferred-size', arguments, only: ms)
     vendor('flex-basis', arguments, only: webkit official)
 
 flex-shrink()
   if flex in flex-version
+    vendor('flex-negative', arguments, only: ms)
     vendor('flex-shrink', arguments, only: webkit official)
 
 flex(growth)
diff --git a/test/cases/flex.css b/test/cases/flex.css
index 49665e64..fa2f3d23 100644
--- a/test/cases/flex.css
+++ b/test/cases/flex.css
@@ -245,6 +245,13 @@ section {
   display: -ms-inline-flexbox !important;
   display: inline-box !important;
 }
+section {
+  -webkit-box-flex: 1;
+  -moz-box-flex: 1;
+  -o-box-flex: 1;
+  -ms-box-flex: 1;
+  box-flex: 1;
+}
 section {
   display: -webkit-flex;
   display: flex;
@@ -269,3 +276,18 @@ section {
   display: -webkit-inline-flex !important;
   display: inline-flex !important;
 }
+section {
+  -ms-flex-positive: 1;
+  -webkit-flex-grow: 1;
+  flex-grow: 1;
+}
+section {
+  -ms-flex-negative: 0;
+  -webkit-flex-shrink: 0;
+  flex-shrink: 0;
+}
+section {
+  -ms-flex-preferred-size: 50%;
+  -webkit-flex-basis: 50%;
+  flex-basis: 50%;
+}
diff --git a/test/cases/flex.styl b/test/cases/flex.styl
index e1a8df1c..8735f1a6 100644
--- a/test/cases/flex.styl
+++ b/test/cases/flex.styl
@@ -72,6 +72,9 @@ section
 section
   display: inline-flex !important
 
+section
+  flex-grow 1
+
 // New property conditional rendering
 flex-version = flex
 
@@ -90,3 +93,12 @@ section
 
 section
   display: inline-flex !important
+
+section
+  flex-grow 1
+
+section
+  flex-shrink 0
+
+section
+  flex-basis 50%