diff --git a/lodash/lodash-tests.ts b/lodash/lodash-tests.ts
index 3afc49041..66fc5cab3 100644
--- a/lodash/lodash-tests.ts
+++ b/lodash/lodash-tests.ts
@@ -2102,23 +2102,6 @@ module TestMap {
     }
 }
 
-result = <number>_.sum([4, 2, 8, 6]);
-result = <number>_.sum([4, 2, 8, 6], function(v) { return v; });
-result = <number>_.sum({a: 2, b: 4});
-result = <number>_.sum({a: 2, b: 4}, function(v) { return v; });
-result = <number>_.sum(stoogesAges, function (stooge) { return stooge.age; });
-result = <number>_.sum(stoogesAges, 'age');
-result = <number>_.sum(stoogesAgesDict, function(stooge) { return stooge.age; });
-result = <number>_.sum(stoogesAgesDict, 'age');
-result = <number>_([4, 2, 8, 6]).sum();
-result = <number>_([4, 2, 8, 6]).sum(function(v) { return v; });
-result = <number>_({a: 2, b: 4}).sum();
-result = <number>_({a: 2, b: 4}).sum(function(v) { return v; });
-result = <number>_(stoogesAges).sum(function (stooge) { return stooge.age; });
-result = <number>_(stoogesAges).sum('age');
-result = <number>_(stoogesAgesDict).sum(function (stooge) { return stooge.age; });
-result = <number>_(stoogesAgesDict).sum('age');
-
 result = <string[]>_.pluck(stoogesAges, 'name');
 result = <string[]>_(stoogesAges).pluck('name').value();
 result = <string[]>_.pluck(stoogesAges, ['name']);
@@ -3152,6 +3135,75 @@ module TestRound {
     }
 }
 
+// _.sum
+module TestSum {
+    let array: number[];
+    let list: _.List<number>;
+    let dictionary: _.Dictionary<number>;
+
+    let listIterator: (value: number, index: number, collection: _.List<number>) => number;
+    let dictionaryIterator: (value: number, key: string, collection: _.Dictionary<number>) => number;
+
+    {
+        let result: number;
+
+        result = _.sum(array);
+        result = _.sum<number>(array);
+        result = _.sum<number>(array, listIterator);
+        result = _.sum<number>(array, listIterator, any);
+        result = _.sum<number>(array, '');
+
+
+        result = _.sum(list);
+        result = _.sum<number>(list);
+        result = _.sum<number>(list, listIterator);
+        result = _.sum<number>(list, listIterator, any);
+        result = _.sum<number>(list, '');
+
+        result = _.sum(dictionary);
+        result = _.sum<number>(dictionary);
+        result = _.sum<number>(dictionary, dictionaryIterator);
+        result = _.sum<number>(dictionary, dictionaryIterator, any);
+        result = _.sum<number>(dictionary, '');
+
+        result = _(array).sum();
+        result = _(array).sum(listIterator);
+        result = _(array).sum(listIterator, any);
+        result = _(array).sum('');
+
+
+        result = _(list).sum();
+        result = _(list).sum<number>(listIterator);
+        result = _(list).sum<number>(listIterator, any);
+        result = _(list).sum('');
+
+        result = _(dictionary).sum();
+        result = _(dictionary).sum<number>(dictionaryIterator);
+        result = _(dictionary).sum<number>(dictionaryIterator, any);
+        result = _(dictionary).sum('');
+    }
+
+    {
+        let result: _.LoDashExplicitWrapper<number>;
+
+        result = _(array).chain().sum();
+        result = _(array).chain().sum(listIterator);
+        result = _(array).chain().sum(listIterator, any);
+        result = _(array).chain().sum('');
+
+
+        result = _(list).chain().sum();
+        result = _(list).chain().sum<number>(listIterator);
+        result = _(list).chain().sum<number>(listIterator, any);
+        result = _(list).chain().sum('');
+
+        result = _(dictionary).chain().sum();
+        result = _(dictionary).chain().sum<number>(dictionaryIterator);
+        result = _(dictionary).chain().sum<number>(dictionaryIterator, any);
+        result = _(dictionary).chain().sum('');
+    }
+}
+
 /**********
  * Number *
  **********/
diff --git a/lodash/lodash.d.ts b/lodash/lodash.d.ts
index f4690176d..c16c3a1f3 100644
--- a/lodash/lodash.d.ts
+++ b/lodash/lodash.d.ts
@@ -4538,136 +4538,6 @@ declare module _ {
         ): LoDashImplicitArrayWrapper<boolean>;
     }
 
-    //_.sum
-    interface LoDashStatic {
-        /**
-        * Gets the sum of the values in collection.
-        *
-        * @param collection The collection to iterate over.
-        * @param iteratee The function invoked per iteration.
-        * @param thisArg The this binding of iteratee.
-        * @return Returns the sum.
-        **/
-        sum(
-            collection: Array<number>): number;
-
-        /**
-        * @see _.sum
-        **/
-        sum(
-            collection: List<number>): number;
-
-        /**
-        * @see _.sum
-        **/
-        sum(
-            collection: Dictionary<number>): number;
-
-        /**
-        * @see _.sum
-        **/
-        sum<T>(
-            collection: Array<T>,
-            iteratee: ListIterator<T, number>,
-            thisArg?: any): number;
-
-        /**
-        * @see _.sum
-        **/
-        sum<T>(
-            collection: List<T>,
-            iteratee: ListIterator<T, number>,
-            thisArg?: any): number;
-
-        /**
-        * @see _.sum
-        **/
-        sum<T>(
-            collection: Dictionary<T>,
-            iteratee: ObjectIterator<T, number>,
-            thisArg?: any): number;
-
-        /**
-        * @see _.sum
-        * @param property _.property callback shorthand.
-        **/
-        sum<T>(
-            collection: Array<T>,
-            property: string): number;
-
-        /**
-        * @see _.sum
-        * @param property _.property callback shorthand.
-        **/
-        sum<T>(
-            collection: List<T>,
-            property: string): number;
-
-        /**
-        * @see _.sum
-        * @param property _.property callback shorthand.
-        **/
-        sum<T>(
-            collection: Dictionary<T>,
-            property: string): number;
-    }
-
-    interface LoDashImplicitNumberArrayWrapper {
-        /**
-        * @see _.sum
-        **/
-        sum(): number;
-
-        /**
-        * @see _.sum
-        **/
-        sum(
-            iteratee: ListIterator<number, number>,
-            thisArg?: any): number;
-    }
-
-    interface LoDashImplicitArrayWrapper<T> {
-        /**
-        * @see _.sum
-        **/
-        sum(): number;
-
-        /**
-        * @see _.sum
-        **/
-        sum(
-            iteratee: ListIterator<T, number>,
-            thisArg?: any): number;
-
-        /**
-        * @see _.sum
-        * @param property _.property callback shorthand.
-        **/
-        sum(
-            property: string): number;
-    }
-
-    interface LoDashImplicitObjectWrapper<T> {
-        /**
-        * @see _.sum
-        **/
-        sum(): number;
-
-        /**
-        * @see _.sum
-        **/
-        sum(
-            iteratee: ObjectIterator<any, number>,
-            thisArg?: any): number;
-
-        /**
-        * @see _.sum
-        * @param property _.property callback shorthand.
-        **/
-        sum(
-            property: string): number;
-    }
-
     //_.pluck
     interface LoDashStatic {
         /**
@@ -7760,6 +7630,130 @@ declare module _ {
         round(precision?: number): LoDashExplicitWrapper<number>;
     }
 
+    //_.sum
+    interface LoDashStatic {
+        /**
+         * Gets the sum of the values in collection.
+         *
+         * @param collection The collection to iterate over.
+         * @param iteratee The function invoked per iteration.
+         * @param thisArg The this binding of iteratee.
+         * @return Returns the sum.
+         */
+        sum<T>(
+            collection: List<T>,
+            iteratee: ListIterator<T, number>,
+            thisArg?: any
+        ): number;
+
+        /**
+         * @see _.sum
+         **/
+        sum<T>(
+            collection: Dictionary<T>,
+            iteratee: DictionaryIterator<T, number>,
+            thisArg?: any
+        ): number;
+
+        /**
+         * @see _.sum
+         */
+        sum<T>(
+            collection: List<number>|Dictionary<number>,
+            iteratee: string
+        ): number;
+
+        /**
+         * @see _.sum
+         */
+        sum<T>(collection: List<T>|Dictionary<T>): number;
+
+        /**
+         * @see _.sum
+         */
+        sum(collection: List<number>|Dictionary<number>): number;
+    }
+
+    interface LoDashImplicitArrayWrapper<T> {
+        /**
+         * @see _.sum
+         */
+        sum(
+            iteratee: ListIterator<T, number>,
+            thisArg?: any
+        ): number;
+
+        /**
+         * @see _.sum
+         */
+        sum(iteratee: string): number;
+
+        /**
+         * @see _.sum
+         */
+        sum(): number;
+    }
+
+    interface LoDashImplicitObjectWrapper<T> {
+        /**
+         * @see _.sum
+         **/
+        sum<TValue>(
+            iteratee: ListIterator<TValue, number>|DictionaryIterator<TValue, number>,
+            thisArg?: any
+        ): number;
+
+        /**
+         * @see _.sum
+         */
+        sum(iteratee: string): number;
+
+        /**
+         * @see _.sum
+         */
+        sum(): number;
+    }
+
+    interface LoDashExplicitArrayWrapper<T> {
+        /**
+         * @see _.sum
+         */
+        sum(
+            iteratee: ListIterator<T, number>,
+            thisArg?: any
+        ): LoDashExplicitWrapper<number>;
+
+        /**
+         * @see _.sum
+         */
+        sum(iteratee: string): LoDashExplicitWrapper<number>;
+
+        /**
+         * @see _.sum
+         */
+        sum(): LoDashExplicitWrapper<number>;
+    }
+
+    interface LoDashExplicitObjectWrapper<T> {
+        /**
+         * @see _.sum
+         */
+        sum<TValue>(
+            iteratee: ListIterator<TValue, number>|DictionaryIterator<TValue, number>,
+            thisArg?: any
+        ): LoDashExplicitWrapper<number>;
+
+        /**
+         * @see _.sum
+         */
+        sum(iteratee: string): LoDashExplicitWrapper<number>;
+
+        /**
+         * @see _.sum
+         */
+        sum(): LoDashExplicitWrapper<number>;
+    }
+
     /**********
      * Number *
      **********/