diff --git a/build.js b/build.js
index 0c0186aff..2a6caeddb 100755
--- a/build.js
+++ b/build.js
@@ -381,21 +381,26 @@
       ].join('\n' + indent);
     });
 
-    // add `__chain__` checks to `_.mixin`
-    source = source.replace(matchFunction(source, 'mixin'), function(match) {
-      return match.replace(/^( *)return new lodash.+/m, function() {
-        var indent = arguments[1];
-        return indent + [
-          '',
-          'var result = func.apply(lodash, args);',
-          'if (this.__chain__) {',
-          '  result = new lodash(result);',
-          '  result.__chain__ = true;',
-          '}',
-          'return result;'
-        ].join('\n' + indent);
-      });
-    });
+    // replace `_.mixin`
+    source = replaceFunction(source, 'mixin', [
+      'function mixin(object) {',
+      '  forEach(functions(object), function(methodName) {',
+      '    var func = lodash[methodName] = object[methodName];',
+      '',
+      '    lodash.prototype[methodName] = function() {',
+      '      var args = [this.__wrapped__];',
+      '      push.apply(args, arguments);',
+      '',
+      '      var result = func.apply(lodash, args);',
+      '      if (this.__chain__) {',
+      '        result = createWrapper(result);',
+      '        result.__chain__ = true;',
+      '      }',
+      '      return result;',
+      '    };',
+      '  });',
+      '}'
+    ].join('\n'));
 
     // replace wrapper `Array` method assignments
     source = source.replace(/^(?: *\/\/.*\n)*( *)each\(\['[\s\S]+?\n\1}$/m, function(match, indent) {
@@ -1174,7 +1179,7 @@
 
     // remove `noCharByIndex` from `_.toArray`
     source = source.replace(matchFunction(source, 'toArray'), function(match) {
-      return match.replace(/noCharByIndex[^:]+:/, '');
+      return match.replace(/(return\b).+?noCharByIndex[^:]+:\s*/, '$1 ');
     });
 
     // `noCharByIndex` from `iteratorTemplate`
@@ -1753,7 +1758,7 @@
       if (isModern) {
         // remove `_.isPlainObject` fallback
         source = source.replace(matchFunction(source, 'isPlainObject'), function(match) {
-          return match.replace(/!getPrototypeOf.+?: */, '');
+          return match.replace(/!getPrototypeOf[^:]+:\s*/, '');
         });
 
         if (!isMobile) {
@@ -1927,7 +1932,7 @@
           '  }',
           '  var isArr = className == arrayClass;',
           '  if (!isArr) {',
-          '    if (a.__wrapped__ || b.__wrapped__) {',
+          '    if (a instanceof lodash || b instanceof lodash) {',
           '      return isEqual(a.__wrapped__ || a, b.__wrapped__ || b, stackA, stackB);',
           '    }',
           '    if (className != objectClass) {',
@@ -1989,6 +1994,19 @@
           '}'
         ].join('\n'));
 
+        // replace `lodash`
+        source = replaceFunction(source, 'lodash', [
+          'function lodash(value) {',
+          '  if (value instanceof lodash) {',
+          '    return value;',
+          '  }',
+          '  if (!(this instanceof lodash)) {',
+          '    return new lodash(value);',
+          '  }',
+          '  this.__wrapped__ = value;',
+          '}'
+        ].join('\n'));
+
         // replace `_.omit`
         source = replaceFunction(source, 'omit', [
           'function omit(object) {',
@@ -2189,7 +2207,7 @@
         // remove conditional `charCodeCallback` use from `_.max` and `_.min`
         _.each(['max', 'min'], function(methodName) {
           source = source.replace(matchFunction(source, methodName), function(match) {
-            return match.replace(/!callback *&& *isString\(collection\)[\s\S]+?: */g, '');
+            return match.replace(/(return\b).+?callback *&& *isString[^:]+:\s*/g, '$1 ');
           });
         });
 
@@ -2469,9 +2487,14 @@
             '  lodash[methodName] = func;',
             '',
             '  lodash.prototype[methodName] = function() {',
-            '    var args = [this.__wrapped__];',
+            '    var value = this.__wrapped__,',
+            '        args = [value];',
+            '',
             '    push.apply(args, arguments);',
-            '    return new lodash(func.apply(lodash, args));',
+            '    var result = func.apply(lodash, args);',
+            "    return (value && typeof value == 'object' && value == result)",
+            '      ? this',
+            '      : createWrapper(result);',
             '  };',
             '});'
           ].join('\n' + indent);
diff --git a/lodash.js b/lodash.js
index ca8c88cc9..a4770b5c4 100644
--- a/lodash.js
+++ b/lodash.js
@@ -174,6 +174,7 @@
 
     /* Native method shortcuts for methods with the same name as other `lodash` methods */
     var nativeBind = reNative.test(nativeBind = slice.bind) && nativeBind,
+        nativeCreate = reNative.test(nativeCreate = Object.create) && nativeCreate,
         nativeIsArray = reNative.test(nativeIsArray = Array.isArray) && nativeIsArray,
         nativeIsFinite = context.isFinite,
         nativeIsNaN = context.isNaN,
@@ -319,7 +320,7 @@
      */
     function lodash(value) {
       // exit early if already wrapped, even if wrapped by a different `lodash` constructor
-      if (value && typeof value == 'object' && value.__wrapped__) {
+      if (value && typeof value == 'object' && hasOwnProperty.call(value, '__wrapped__')) {
         return value;
       }
       // allow invoking `lodash` without the `new` operator
@@ -644,9 +645,7 @@
         }
         if (this instanceof bound) {
           // ensure `new bound` is an instance of `func`
-          noop.prototype = func.prototype;
-          thisBinding = new noop;
-          noop.prototype = null;
+          thisBinding = createObject(func.prototype);
 
           // mimic the constructor's `return` behavior
           // http://es5.github.com/#x13.2.2
@@ -769,6 +768,33 @@
       );
     }
 
+    /**
+     * Creates a new object that inherits from the given `prototype` object.
+     *
+     * @private
+     * @param {Object} prototype The prototype object.
+     * @returns {Object} Returns the new object.
+     */
+    var createObject = nativeCreate || function(prototype) {
+      noop.prototype = prototype;
+      var result = new noop;
+      noop.prototype = null;
+      return result;
+    };
+
+    /**
+     * A fast path for creating `lodash` wrapper objects.
+     *
+     * @private
+     * @param {Mixed} value The value to wrap in a `lodash` instance.
+     * @returns {Object} Returns a `lodash` instance.
+     */
+    function createWrapper(value) {
+      var result = createObject(lodash.prototype);
+      result.__wrapped__ = value;
+      return result;
+    }
+
     /**
      * A function compiled to iterate `arguments` objects, arrays, objects, and
      * strings consistenly across environments, executing the `callback` for each
@@ -1562,7 +1588,7 @@
 
         case numberClass:
           // treat `NaN` vs. `NaN` as equal
-          return a != +a
+          return (a != +a)
             ? b != +b
             // but treat `+0` vs. `-0` as not equal
             : (a == 0 ? (1 / a == 1 / b) : a == +b);
@@ -1576,7 +1602,7 @@
       var isArr = className == arrayClass;
       if (!isArr) {
         // unwrap any `lodash` wrapped values
-        if (a.__wrapped__ || b.__wrapped__) {
+        if (hasOwnProperty.call(a, '__wrapped__ ') || hasOwnProperty.call(b, '__wrapped__')) {
           return isEqual(a.__wrapped__ || a, b.__wrapped__ || b, callback, thisArg, stackA, stackB);
         }
         // exit for functions and DOM nodes
@@ -2748,7 +2774,7 @@
           }
         }
       } else {
-        callback = !callback && isString(collection)
+        callback = (!callback && isString(collection))
           ? charAtCallback
           : createCallback(callback, thisArg);
 
@@ -2817,7 +2843,7 @@
           }
         }
       } else {
-        callback = !callback && isString(collection)
+        callback = (!callback && isString(collection))
           ? charAtCallback
           : createCallback(callback, thisArg);
 
@@ -3181,7 +3207,7 @@
      */
     function toArray(collection) {
       if (collection && typeof collection.length == 'number') {
-        return noCharByIndex && isString(collection)
+        return (noCharByIndex && isString(collection))
           ? collection.split('')
           : slice(collection);
       }
@@ -3848,7 +3874,7 @@
 
       while (low < high) {
         var mid = (low + high) >>> 1;
-        callback(array[mid]) < value
+        (callback(array[mid]) < value)
           ? low = mid + 1
           : high = mid;
       }
@@ -4573,9 +4599,14 @@
         var func = lodash[methodName] = object[methodName];
 
         lodash.prototype[methodName] = function() {
-          var args = [this.__wrapped__];
+          var value = this.__wrapped__,
+              args = [value];
+
           push.apply(args, arguments);
-          return new lodash(func.apply(lodash, args));
+          var result = func.apply(lodash, args);
+          return (value && typeof value == 'object' && value == result)
+            ? this
+            : createWrapper(result);
         };
       });
     }
@@ -5130,7 +5161,7 @@
           var result = func(this.__wrapped__, callback, thisArg);
           return callback == null || (thisArg && typeof callback != 'function')
             ? result
-            : new lodash(result);
+            : createWrapper(result);
         };
       }
     });
@@ -5172,7 +5203,7 @@
     each(['concat', 'slice', 'splice'], function(methodName) {
       var func = arrayRef[methodName];
       lodash.prototype[methodName] = function() {
-        return new lodash(func.apply(this.__wrapped__, arguments));
+        return createWrapper(func.apply(this.__wrapped__, arguments));
       };
     });
 
@@ -5190,7 +5221,7 @@
           if (value.length === 0) {
             delete value[0];
           }
-          return isSplice ? new lodash(result) : result;
+          return isSplice ? createWrapper(result) : result;
         };
       });
     }
diff --git a/test/test.js b/test/test.js
index 2df29a69f..126754dba 100644
--- a/test/test.js
+++ b/test/test.js
@@ -179,8 +179,8 @@
       ok(_() instanceof _);
     });
 
-    test('should return passed LoDash instances', function() {
-      var wrapped = _([]);
+    test('should return passed `lodash` instances', function() {
+      var wrapped = _(false);
       equal(_(wrapped), wrapped);
     });
   }());
@@ -810,11 +810,16 @@
   QUnit.module('lodash.forEach');
 
   (function() {
-    test('returns the collection', function() {
+    test('should return the collection', function() {
       var collection = [1, 2, 3];
       equal(_.forEach(collection, Boolean), collection);
     });
 
+    test('should return the existing wrapper when chaining', function() {
+      var wrapper = _([1, 2, 3]);
+      equal(wrapper.forEach(Boolean), wrapper);
+    });
+
     _.each({
       'literal': 'abc',
       'object': Object('abc')
@@ -901,6 +906,12 @@
   _.each(['assign', 'defaults', 'merge'], function(methodName) {
     var func = _[methodName];
 
+    test('should return the existing wrapper when chaining', function() {
+      var wrapper = _({ 'a': 1 });
+      equal(wrapper[methodName]({ 'b': 2 }), wrapper);
+    });
+
+
     test('lodash.' + methodName + ' should assign problem JScript properties (test in IE < 9)', function() {
       var object = {
         'constructor': '0',