diff --git a/src/company_gui.cpp b/src/company_gui.cpp
index 8bd575f641..4f2dd2660e 100644
--- a/src/company_gui.cpp
+++ b/src/company_gui.cpp
@@ -2687,7 +2687,7 @@ struct CompanyWindow : Window
 			default: NOT_REACHED();
 
 			case WID_C_GIVE_MONEY:
-				DoCommandP(0, (atoi(str) / _currency->rate), this->window_number, CMD_GIVE_MONEY | CMD_MSG(STR_ERROR_INSUFFICIENT_FUNDS), CcGiveMoney, str);
+				DoCommandP(0, (strtoull(str, nullptr, 10) / _currency->rate), this->window_number, CMD_GIVE_MONEY | CMD_MSG(STR_ERROR_INSUFFICIENT_FUNDS), CcGiveMoney, str);
 				break;
 
 			case WID_C_PRESIDENT_NAME: