diff --git a/src/__tests__/__snapshots__/indexBy-test.js.snap b/src/__tests__/__snapshots__/indexBy-test.js.snap
index ee3ee41..2b433ac 100644
--- a/src/__tests__/__snapshots__/indexBy-test.js.snap
+++ b/src/__tests__/__snapshots__/indexBy-test.js.snap
@@ -1,7 +1,7 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`transmute/indexBy indexes a List 1`] = `
-Immutable.Map {
+Immutable.OrderedMap {
   "123": Immutable.Map {
     "id": "123",
   },
@@ -23,7 +23,7 @@ Immutable.Map {
 `;
 
 exports[`transmute/indexBy indexes an Array 1`] = `
-Object {
+Immutable.OrderedMap {
   "123": Immutable.Map {
     "id": "123",
   },
@@ -34,7 +34,7 @@ Object {
 `;
 
 exports[`transmute/indexBy indexes an Object 1`] = `
-Object {
+Immutable.OrderedMap {
   "123": Object {
     "id": "123",
   },
diff --git a/src/indexBy.js b/src/indexBy.js
index 6b72970..f146d48 100644
--- a/src/indexBy.js
+++ b/src/indexBy.js
@@ -1,13 +1,13 @@
-import _keyedEquivalent from './internal/_keyedEquivalent';
 import _reduce from './internal/_reduce';
-import _set from './internal/_set';
 import curry from './curry';
 import { Iterable, Map, OrderedMap } from 'immutable';
 
 function indexBy(keyMapper, subject) {
   return _reduce(
-    _keyedEquivalent(subject),
-    (acc, v, k) => _set(keyMapper(v, k, subject), v, acc),
+    Iterable.isOrdered(subject) || !Iterable.isIterable(subject)
+      ? OrderedMap()
+      : Map(),
+    (acc, v, k) => acc.set(keyMapper(v, k, subject), v),
     subject
   );
 }
diff --git a/src/internal/_keyedEquivalent.js b/src/internal/_keyedEquivalent.js
index b95dcfd..8eea5bc 100644
--- a/src/internal/_keyedEquivalent.js
+++ b/src/internal/_keyedEquivalent.js
@@ -1,4 +1,4 @@
-import { Collection, Iterable, Map, Seq } from 'immutable';
+import { Collection, Map, Seq } from 'immutable';
 import { keyedEquivalent } from './TransmuteCollection';
 
 const makeObject = () => ({});