diff --git a/README.md b/README.md
index fbd6615b..847de555 100644
--- a/README.md
+++ b/README.md
@@ -87,6 +87,13 @@ console.log(SteamUser.formatCurrency(123.45, SteamUser.ECurrencyCode.EUR)); // 1
 
 There are a number of options which can control the behavior of the `SteamUser` object. They are:
 
+### accountIdentifier
+
+A string which identifies the account. This is not the same as your SteamID.
+It's used as salt for internal methods, for example when generating the machineId.
+
+Defaults to `null`, which means internal methods will be used to select a proper identifier.
+
 ### dataDirectory
 
 Controls where the Steam server list and machine auth token files are written. If `null`, no data will be automatically
diff --git a/components/09-logon.js b/components/09-logon.js
index 010914b2..20a4b486 100644
--- a/components/09-logon.js
+++ b/components/09-logon.js
@@ -596,7 +596,8 @@ class SteamUserLogon extends SteamUserMachineAuth {
 	}
 
 	_getAccountIdentifier() {
-		return this._logOnDetails.account_name
+		return this.options.accountIdentifier
+			|| this._logOnDetails.account_name
 			|| this._logOnDetails._newAuthAccountName
 			|| this._logOnDetails._steamid.toString();
 	}
diff --git a/resources/default_options.js b/resources/default_options.js
index bdd51483..6250985d 100644
--- a/resources/default_options.js
+++ b/resources/default_options.js
@@ -3,6 +3,7 @@ const EMachineIDType = require('./EMachineIDType.js');
 
 /**
  * @typedef {object} OptionsObject
+ * @property {string|null} [accountIdentifier]
  * @property {string|null} [dataDirectory]
  * @property {boolean} [autoRelogin=true]
  * @property {EMachineIDType} [machineIdType]
@@ -25,6 +26,7 @@ const EMachineIDType = require('./EMachineIDType.js');
 
 module.exports = {
 	autoRelogin: true,
+	accountIdentifier: null,
 	machineIdType: EMachineIDType.AccountNameGenerated,
 	machineIdFormat: ['SteamUser Hash BB3 {account_name}', 'SteamUser Hash FF2 {account_name}', 'SteamUser Hash 3B3 {account_name}'],
 	enablePicsCache: false,