diff --git a/lib/chai-as-promised.js b/lib/chai-as-promised.js
index c6808e0..78dfb0e 100644
--- a/lib/chai-as-promised.js
+++ b/lib/chai-as-promised.js
@@ -105,7 +105,6 @@
             var that = this;
             var derivedPromise = getBasePromise(that).then(
                 function (value) {
-                    that._obj = value;
                     assertIfNegated(that,
                                     "expected promise not to be fulfilled but it was fulfilled with #{act}",
                                     { actual: value });
@@ -115,6 +114,7 @@
                     assertIfNotNegated(that,
                                        "expected promise to be fulfilled but it was rejected with #{act}",
                                        { actual: reason });
+                    return reason;
                 }
             );
 
@@ -125,7 +125,6 @@
             var that = this;
             var derivedPromise = getBasePromise(that).then(
                 function (value) {
-                    that._obj = value;
                     assertIfNotNegated(that,
                                        "expected promise to be rejected but it was fulfilled with #{act}",
                                        { actual: value });
@@ -183,9 +182,8 @@
                         expected = desiredReason;
                     }
 
-                    that._obj = value;
-
                     assertIfNotNegated(that, assertionMessage, { expected: expected, actual: value });
+                    return value;
                 },
                 function (reason) {
                     if (Constructor) {
@@ -223,6 +221,7 @@
                                     desiredReason,
                                     reason);
                     }
+                    return reason;
                 }
             );