diff --git a/lib/6to5/file.js b/lib/6to5/file.js
index cf7daf2505..f1f0c42768 100644
--- a/lib/6to5/file.js
+++ b/lib/6to5/file.js
@@ -81,7 +81,7 @@ File.prototype.getModuleFormatter = function (type) {
     throw new ReferenceError("unknown module formatter type " + type);
   }
 
-  return new ModuleFormatter(this, opts);
+  return new ModuleFormatter(this);
 };
 
 File.prototype.parseShebang = function (code) {
diff --git a/lib/6to5/transformation/modules/amd.js b/lib/6to5/transformation/modules/amd.js
index 5585a226bd..cfff80012f 100644
--- a/lib/6to5/transformation/modules/amd.js
+++ b/lib/6to5/transformation/modules/amd.js
@@ -5,10 +5,9 @@ var util              = require("../../util");
 var t                 = require("../../types");
 var _                 = require("lodash");
 
-function AMDFormatter(file, opts) {
+function AMDFormatter(file) {
   this.file = file;
   this.ids  = {};
-  this.insertModuleId = opts.amdModuleId;
 }
 
 util.inherits(AMDFormatter, CommonJSFormatter);
@@ -32,10 +31,8 @@ AMDFormatter.prototype.transform = function (ast) {
 
   var container = t.functionExpression(null, params, t.blockStatement(body));
   var defineArgs = [names, container];
-  if (this.insertModuleId) {
-    var moduleName = this.getModuleName();
-    defineArgs.unshift(t.literal(moduleName));
-  }
+  var moduleName = this.getModuleName();
+  if (moduleName) defineArgs.unshift(t.literal(moduleName));
   var call = t.callExpression(t.identifier("define"), defineArgs);
 
   program.body = [t.expressionStatement(call)];
@@ -46,6 +43,10 @@ AMDFormatter.prototype.getModuleName = function () {
   var filenameRelative = opts.filenameRelative;
   var moduleName = "";
 
+  if (!opts.amdModuleId) {
+    return null;
+  }
+
   if (opts.moduleRoot) {
     moduleName = opts.moduleRoot + "/";
   }
diff --git a/lib/6to5/transformation/modules/umd.js b/lib/6to5/transformation/modules/umd.js
index 93d9bafd78..199de38024 100644
--- a/lib/6to5/transformation/modules/umd.js
+++ b/lib/6to5/transformation/modules/umd.js
@@ -32,10 +32,8 @@ UMDFormatter.prototype.transform = function (ast) {
   // runner
 
   var defineArgs = [t.arrayExpression([t.literal("exports")].concat(names))];
-  if (this.insertModuleId) {
-    var moduleName = this.getModuleName();
-    defineArgs.unshift(t.literal(moduleName));
-  }
+  var moduleName = this.getModuleName();
+  if (moduleName) defineArgs.unshift(t.literal(moduleName));
 
   var runner = util.template("umd-runner-body", {
     AMD_ARGUMENTS: defineArgs,