diff --git a/modules/permutiveRtdProvider.js b/modules/permutiveRtdProvider.js
index 8af963f37dc..4ff41627135 100644
--- a/modules/permutiveRtdProvider.js
+++ b/modules/permutiveRtdProvider.js
@@ -146,12 +146,17 @@ function updateOrtbConfig(bidder, currConfig, segmentIDs, sspSegmentIDs, transfo
     .filter(({ id }) => ortb2UserDataTransformations.hasOwnProperty(id))
     .map(({ id, config }) => ortb2UserDataTransformations[id](permutiveUserData, config))
 
+  const customCohortsUserData = {
+    name: PERMUTIVE_CUSTOM_COHORTS_KEYWORD,
+    segment: customCohortsData.map(cohortID => ({ id: cohortID })),
+  }
+
   const ortbConfig = mergeDeep({}, currConfig)
   const currentUserData = deepAccess(ortbConfig, 'ortb2.user.data') || []
 
   const updatedUserData = currentUserData
-    .filter(el => el.name !== name)
-    .concat(permutiveUserData, transformedUserData)
+    .filter(el => el.name !== permutiveUserData.name && el.name !== customCohortsUserData.name)
+    .concat(permutiveUserData, transformedUserData, customCohortsUserData)
 
   deepSetValue(ortbConfig, 'ortb2.user.data', updatedUserData)
 
@@ -311,6 +316,7 @@ export function getSegments (maxSegs) {
 
   const segments = {
     ac: [..._pcrprs, ..._ppam, ...legacySegs],
+    ix: readSegments('_pindexs', []),
     rubicon: readSegments('_prubicons', []),
     appnexus: readSegments('_papns', []),
     gam: readSegments('_pdfps', []),
diff --git a/test/spec/modules/permutiveRtdProvider_spec.js b/test/spec/modules/permutiveRtdProvider_spec.js
index 207771731a7..18d413acdad 100644
--- a/test/spec/modules/permutiveRtdProvider_spec.js
+++ b/test/spec/modules/permutiveRtdProvider_spec.js
@@ -196,12 +196,67 @@ describe('permutiveRtdProvider', function () {
       setBidderRtb(bidderConfig, moduleConfig, segmentsData)
 
       acBidders.forEach(bidder => {
-        expect(bidderConfig[bidder].user.data).to.deep.include.members([{
-          name: 'permutive.com',
-          segment: expectedTargetingData
-        }])
+        const customCohorts = segmentsData[bidder] || []
+        expect(bidderConfig[bidder].user.data).to.deep.include.members([
+          {
+            name: 'permutive.com',
+            segment: expectedTargetingData,
+          },
+          // Should have custom cohorts specific for that bidder
+          {
+            name: 'permutive',
+            segment: customCohorts.map(seg => {
+              return { id: seg }
+            }),
+          },
+        ])
       })
     })
+
+    it('should override existing ortb2.user.data reserved by permutive RTD', function () {
+      const reservedPermutiveStandardName = 'permutive.com'
+      const reservedPermutiveCustomCohortName = 'permutive'
+
+      const moduleConfig = getConfig()
+      const acBidders = moduleConfig.params.acBidders
+      const segmentsData = transformedTargeting()
+
+      const sampleOrtbConfig = {
+        user: {
+          data: [
+            {
+              name: reservedPermutiveCustomCohortName,
+              segment: [{ id: 'remove-me' }, { id: 'remove-me-also' }]
+            },
+            {
+              name: reservedPermutiveStandardName,
+              segment: [{ id: 'remove-me-also-also' }, { id: 'remove-me-also-also-also' }]
+            }
+          ]
+        }
+      }
+
+      const bidderConfig = Object.fromEntries(acBidders.map(bidder => [bidder, sampleOrtbConfig]))
+
+      setBidderRtb(bidderConfig, moduleConfig, segmentsData)
+
+      acBidders.forEach(bidder => {
+        const customCohorts = segmentsData[bidder] || []
+
+        expect(bidderConfig[bidder].user.data).to.not.deep.include.members([...sampleOrtbConfig.user.data])
+        expect(bidderConfig[bidder].user.data).to.deep.include.members([
+          {
+            name: reservedPermutiveCustomCohortName,
+            segment: customCohorts.map(id => ({ id })),
+          },
+          {
+            name: reservedPermutiveStandardName,
+            segment: segmentsData.ac.map(id => ({ id })),
+          },
+        ])
+      })
+    })
+
     it('should include ortb2 user data transformation for IAB audience taxonomy', function() {
       const moduleConfig = getConfig()
       const bidderConfig = {}
@@ -647,6 +702,7 @@ function transformedTargeting (data = getTargetingData()) {
   return {
     ac: [...data._pcrprs, ...data._ppam, ...data._psegs.filter(seg => seg >= 1000000)],
     appnexus: data._papns,
+    ix: data._pindexs,
     rubicon: data._prubicons,
     gam: data._pdfps,
     ssp: data._pssps,
@@ -660,6 +716,7 @@ function getTargetingData () {
     _papns: ['appnexus1', 'appnexus2'],
     _psegs: ['1234', '1000001', '1000002'],
     _ppam: ['ppam1', 'ppam2'],
+    _pindexs: ['pindex1', 'pindex2'],
     _pcrprs: ['pcrprs1', 'pcrprs2', 'dup'],
     _pssps: { ssps: ['xyz', 'abc', 'dup'], cohorts: ['123', 'abc'] }
   }