diff --git a/lib/branches/normalize.js b/lib/branches/normalize.js
index 4e3e9b01f0..103519c10b 100644
--- a/lib/branches/normalize.js
+++ b/lib/branches/normalize.js
@@ -91,6 +91,7 @@ function release({release}) {
       name,
       range: getRange(min, bound),
       accept: bound ? RELEASE_TYPE.slice(0, RELEASE_TYPE.indexOf(diff)) : RELEASE_TYPE,
+      main: idx === 0,
     };
   });
 }
diff --git a/test/branches/normalize.test.js b/test/branches/normalize.test.js
index d137af41e5..b7e01a1a13 100644
--- a/test/branches/normalize.test.js
+++ b/test/branches/normalize.test.js
@@ -155,16 +155,26 @@ test('Release branches - initial state', t => {
   ];
 
   t.deepEqual(
-    normalize.release({release}).map(({type, name, range, accept, channel}) => ({type, name, range, accept, channel})),
+    normalize
+      .release({release})
+      .map(({type, name, range, accept, channel, main}) => ({type, name, range, accept, channel, main})),
     [
-      {type: 'release', name: 'master', range: '>=1.0.0 <1.1.0', accept: ['patch'], channel: undefined},
-      {type: 'release', name: 'next', range: '>=1.1.0 <2.0.0', accept: ['patch', 'minor'], channel: 'next'},
+      {type: 'release', name: 'master', range: '>=1.0.0 <1.1.0', accept: ['patch'], channel: undefined, main: true},
+      {
+        type: 'release',
+        name: 'next',
+        range: '>=1.1.0 <2.0.0',
+        accept: ['patch', 'minor'],
+        channel: 'next',
+        main: false,
+      },
       {
         type: 'release',
         name: 'next-major',
         range: '>=2.0.0',
         accept: ['patch', 'minor', 'major'],
         channel: 'next-major',
+        main: false,
       },
     ]
   );
@@ -178,16 +188,26 @@ test('Release branches - 3 release branches', t => {
   ];
 
   t.deepEqual(
-    normalize.release({release}).map(({type, name, range, accept, channel}) => ({type, name, range, accept, channel})),
+    normalize
+      .release({release})
+      .map(({type, name, range, accept, channel, main}) => ({type, name, range, accept, channel, main})),
     [
-      {type: 'release', name: 'master', range: '>=1.0.2 <1.1.0', accept: ['patch'], channel: undefined},
-      {type: 'release', name: 'next', range: '>=1.2.0 <2.0.0', accept: ['patch', 'minor'], channel: 'next'},
+      {type: 'release', name: 'master', range: '>=1.0.2 <1.1.0', accept: ['patch'], channel: undefined, main: true},
+      {
+        type: 'release',
+        name: 'next',
+        range: '>=1.2.0 <2.0.0',
+        accept: ['patch', 'minor'],
+        channel: 'next',
+        main: false,
+      },
       {
         type: 'release',
         name: 'next-major',
         range: '>=2.1.0',
         accept: ['patch', 'minor', 'major'],
         channel: 'next-major',
+        main: false,
       },
     ]
   );
@@ -200,10 +220,26 @@ test('Release branches - 2 release branches', t => {
   ];
 
   t.deepEqual(
-    normalize.release({release}).map(({type, name, range, accept, channel}) => ({type, name, range, accept, channel})),
+    normalize
+      .release({release})
+      .map(({type, name, range, accept, channel, main}) => ({type, name, range, accept, channel, main})),
     [
-      {type: 'release', name: 'master', range: '>=1.2.0 <2.0.0', accept: ['patch', 'minor'], channel: undefined},
-      {type: 'release', name: 'next', range: '>=2.1.0', accept: ['patch', 'minor', 'major'], channel: 'next'},
+      {
+        type: 'release',
+        name: 'master',
+        range: '>=1.2.0 <2.0.0',
+        accept: ['patch', 'minor'],
+        channel: undefined,
+        main: true,
+      },
+      {
+        type: 'release',
+        name: 'next',
+        range: '>=2.1.0',
+        accept: ['patch', 'minor', 'major'],
+        channel: 'next',
+        main: false,
+      },
     ]
   );
 });
@@ -225,16 +261,19 @@ test('Release branches - cap ranges to first release only present on following b
   ];
 
   t.deepEqual(
-    normalize.release({release}).map(({type, name, range, accept, channel}) => ({type, name, range, accept, channel})),
+    normalize
+      .release({release})
+      .map(({type, name, range, accept, channel, main}) => ({type, name, range, accept, channel, main})),
     [
-      {type: 'release', name: 'master', range: '>=2.0.0 <2.1.0', accept: ['patch'], channel: undefined},
-      {type: 'release', name: 'next', range: '>=2.1.0 <2.2.0', accept: ['patch'], channel: 'next'},
+      {type: 'release', name: 'master', range: '>=2.0.0 <2.1.0', accept: ['patch'], channel: undefined, main: true},
+      {type: 'release', name: 'next', range: '>=2.1.0 <2.2.0', accept: ['patch'], channel: 'next', main: false},
       {
         type: 'release',
         name: 'next-major',
         range: '>=2.2.0',
         accept: ['patch', 'minor', 'major'],
         channel: 'next-major',
+        main: false,
       },
     ]
   );
@@ -247,10 +286,26 @@ test('Release branches - Handle missing previous tags in branch history', t => {
   ];
 
   t.deepEqual(
-    normalize.release({release}).map(({type, name, range, accept, channel}) => ({type, name, range, accept, channel})),
+    normalize
+      .release({release})
+      .map(({type, name, range, accept, channel, main}) => ({type, name, range, accept, channel, main})),
     [
-      {type: 'release', name: 'master', range: '>=2.0.0 <3.0.0', accept: ['patch', 'minor'], channel: undefined},
-      {type: 'release', name: 'next', range: '>=3.0.0', accept: ['patch', 'minor', 'major'], channel: 'next'},
+      {
+        type: 'release',
+        name: 'master',
+        range: '>=2.0.0 <3.0.0',
+        accept: ['patch', 'minor'],
+        channel: undefined,
+        main: true,
+      },
+      {
+        type: 'release',
+        name: 'next',
+        range: '>=3.0.0',
+        accept: ['patch', 'minor', 'major'],
+        channel: 'next',
+        main: false,
+      },
     ]
   );
 });
@@ -263,16 +318,26 @@ test('Release branches - enforce release gaps after downstream merge', t => {
   ];
 
   t.deepEqual(
-    normalize.release({release}).map(({type, name, range, accept, channel}) => ({type, name, range, accept, channel})),
+    normalize
+      .release({release})
+      .map(({type, name, range, accept, channel, main}) => ({type, name, range, accept, channel, main})),
     [
-      {type: 'release', name: 'master', range: '>=2.0.0 <2.1.0', accept: ['patch'], channel: undefined},
-      {type: 'release', name: 'next', range: '>=2.1.0 <3.0.0', accept: ['patch', 'minor'], channel: 'next'},
+      {type: 'release', name: 'master', range: '>=2.0.0 <2.1.0', accept: ['patch'], channel: undefined, main: true},
+      {
+        type: 'release',
+        name: 'next',
+        range: '>=2.1.0 <3.0.0',
+        accept: ['patch', 'minor'],
+        channel: 'next',
+        main: false,
+      },
       {
         type: 'release',
         name: 'next-major',
         range: '>=3.0.0',
         accept: ['patch', 'minor', 'major'],
         channel: 'next-major',
+        main: false,
       },
     ]
   );
@@ -286,16 +351,26 @@ test('Release branches - limit releases on 2nd and 3rd branche based on 1st bran
   ];
 
   t.deepEqual(
-    normalize.release({release}).map(({type, name, range, accept, channel}) => ({type, name, range, accept, channel})),
+    normalize
+      .release({release})
+      .map(({type, name, range, accept, channel, main}) => ({type, name, range, accept, channel, main})),
     [
-      {type: 'release', name: 'master', range: '>=3.0.0 <3.1.0', accept: ['patch'], channel: undefined},
-      {type: 'release', name: 'next', range: '>=3.1.0 <4.0.0', accept: ['patch', 'minor'], channel: 'next'},
+      {type: 'release', name: 'master', range: '>=3.0.0 <3.1.0', accept: ['patch'], channel: undefined, main: true},
+      {
+        type: 'release',
+        name: 'next',
+        range: '>=3.1.0 <4.0.0',
+        accept: ['patch', 'minor'],
+        channel: 'next',
+        main: false,
+      },
       {
         type: 'release',
         name: 'next-major',
         range: '>=4.0.0',
         accept: ['patch', 'minor', 'major'],
         channel: 'next-major',
+        main: false,
       },
     ]
   );
diff --git a/test/index.test.js b/test/index.test.js
index 7c86579c30..11f35ca283 100644
--- a/test/index.test.js
+++ b/test/index.test.js
@@ -98,6 +98,7 @@ test('Plugins are called with expected values', async t => {
       accept: ['patch', 'minor'],
       tags: [{channels: ['next'], gitTag: 'v1.0.0@next', version: '1.0.0'}],
       type: 'release',
+      main: true,
     },
     {
       channel: 'next',
@@ -106,6 +107,7 @@ test('Plugins are called with expected values', async t => {
       accept: ['patch', 'minor', 'major'],
       tags: [{channels: ['next'], gitTag: 'v1.0.0@next', version: '1.0.0'}],
       type: 'release',
+      main: false,
     },
   ];
   const branch = branches[0];