diff --git a/README.md b/README.md
index 1c8619896..ec24ba949 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# lodash-es v3.9.2
+# lodash-es v3.9.3
 
 The [modern build](https://github.com/lodash/lodash/wiki/Build-Differences) of [lodash](https://lodash.com/) exported as [ES](https://people.mozilla.org/~jorendorff/es6-draft.html) modules.
 
@@ -7,4 +7,4 @@ Generated using [lodash-cli](https://www.npmjs.com/package/lodash-cli):
 $ lodash modularize modern exports=es -o ./
 ```
 
-See the [package source](https://github.com/lodash/lodash/tree/3.9.2-es) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/3.9.3-es) for more details.
diff --git a/internal/isIndex.js b/internal/isIndex.js
index 73e34d32c..cff7909e1 100644
--- a/internal/isIndex.js
+++ b/internal/isIndex.js
@@ -1,3 +1,6 @@
+/** Used to detect unsigned integer values. */
+var reIsUint = /^\d+$/;
+
 /**
  * Used as the [maximum length](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.max_safe_integer)
  * of an array-like value.
@@ -13,7 +16,7 @@ var MAX_SAFE_INTEGER = 9007199254740991;
  * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
  */
 function isIndex(value, length) {
-  value = typeof value == 'number' ? value : parseFloat(value);
+  value = (typeof value == 'number' || reIsUint.test(value)) ? +value : -1;
   length = length == null ? MAX_SAFE_INTEGER : length;
   return value > -1 && value % 1 == 0 && value < length;
 }
diff --git a/lodash.js b/lodash.js
index 215c3988a..ed20942d3 100644
--- a/lodash.js
+++ b/lodash.js
@@ -1,6 +1,6 @@
 /**
  * @license
- * lodash 3.9.2 (Custom Build) <https://lodash.com/>
+ * lodash 3.9.3 (Custom Build) <https://lodash.com/>
  * Build: `lodash modularize modern exports="es" -o ./`
  * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
  * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
@@ -42,7 +42,7 @@ import support from './support';
 import thru from './chain/thru';
 
 /** Used as the semantic version number. */
-var VERSION = '3.9.2';
+var VERSION = '3.9.3';
 
 /** Used to compose bitmasks for wrapper metadata. */
 var BIND_KEY_FLAG = 2;
diff --git a/package.json b/package.json
index 49ed990eb..c8b0fa245 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "lodash-es",
-  "version": "3.9.2",
+  "version": "3.9.3",
   "description": "The modern build of lodash exported as ES modules.",
   "homepage": "https://lodash.com/custom-builds",
   "license": "MIT",