diff --git i/src/xact.cc w/src/xact.cc
index a0e5b8b4..13edb2e3 100644
--- i/src/xact.cc
+++ w/src/xact.cc
@@ -814,12 +814,18 @@ void auto_xact_t::extend_xact(xact_base_t& xact, parse_context_t& context)
         string fullname = account->fullname();
         assert(! fullname.empty());
 
-        if (contains(fullname, "$account")) {
-          fullname = regex_replace(fullname, regex("\\$account\\>"),
-                                   initial_post->account->fullname());
-          while (account->parent)
-            account = account->parent;
-          account = account->find_account(fullname);
+        const regex re("\\$([A-Za-z_]+)");
+        smatch matches;
+        if (regex_search(fullname, matches, re)) {
+          bind_scope_t bound_scope(*context.scope, *initial_post->account);
+          const string subexpr = matches[1];
+          value_t result = expr_t(subexpr).calc(bound_scope);
+          if (result.is_string()) {
+            fullname = regex_replace(fullname, re, result.as_string());
+            while (account->parent)
+              account = account->parent;
+            account = account->find_account(fullname);
+          }
         }
         else if (contains(fullname, "%(")) {
           format_t account_name(fullname);