diff --git a/lib/reporter.js b/lib/reporter.js
index 9ccbe56..2883600 100644
--- a/lib/reporter.js
+++ b/lib/reporter.js
@@ -138,11 +138,12 @@ var CoverageReporter = function(rootConfig, helper, logger) {
                                                                                            reporterConfig.dir || config.dir,
                                                                                            reporterConfig.subdir || config.subdir)));
           var _ = helper._;
-          var options = helper.merge({}, config, reporterConfig, {
-            dir : outputDir,
+          var options = helper.merge({
             sourceStore : _.isEmpty(sourceCache) ? null : new SourceCacheStore({
               sourceCache: sourceCache
             })
+          }, config, reporterConfig, {
+            dir : outputDir
           });
           var reporter = istanbul.Report.create(reporterConfig.type || 'html', options);