diff --git a/src/ai/api/ai_accounting.cpp b/src/ai/api/ai_accounting.cpp
new file mode 100644
--- /dev/null
+++ b/src/ai/api/ai_accounting.cpp
@@ -0,0 +1,26 @@
+/* $Id$ */
+
+/** @file ai_accounting.cpp Implementation of AIAccounting. */
+
+#include "ai_accounting.hpp"
+
+Money AIAccounting::GetCosts()
+{
+	return this->GetDoCommandCosts();
+}
+
+void AIAccounting::ResetCosts()
+{
+	this->SetDoCommandCosts(0);
+}
+
+AIAccounting::AIAccounting()
+{
+	this->last_costs = this->GetDoCommandCosts();
+	this->SetDoCommandCosts(0);
+}
+
+AIAccounting::~AIAccounting()
+{
+	this->SetDoCommandCosts(this->last_costs);
+}