diff --git a/distribution/changelog.txt b/distribution/changelog.txt
index 46e81b634f..92455e8dcb 100644
--- a/distribution/changelog.txt
+++ b/distribution/changelog.txt
@@ -1,5 +1,6 @@
 0.4.7 (in development)
 ------------------------------------------------------------------------
+- Fix: [#20737] Spent money in player window underflows when getting refunds.
 
 0.4.6 (2023-09-03)
 ------------------------------------------------------------------------
diff --git a/src/openrct2/actions/GameAction.cpp b/src/openrct2/actions/GameAction.cpp
index 637a61520f..efaebc3321 100644
--- a/src/openrct2/actions/GameAction.cpp
+++ b/src/openrct2/actions/GameAction.cpp
@@ -387,7 +387,8 @@ namespace GameActions
                         playerIndex != -1, "Unable to find player %u for game action %u", playerId, action->GetType());
 
                     NetworkSetPlayerLastAction(playerIndex, action->GetType());
-                    if (result.Cost != 0)
+                    NetworkIncrementPlayerNumCommands(playerIndex);
+                    if (result.Cost > 0)
                     {
                         NetworkAddPlayerMoneySpent(playerIndex, result.Cost);
                     }
diff --git a/src/openrct2/network/NetworkBase.cpp b/src/openrct2/network/NetworkBase.cpp
index 038f24ce7d..e205bdb61a 100644
--- a/src/openrct2/network/NetworkBase.cpp
+++ b/src/openrct2/network/NetworkBase.cpp
@@ -3352,6 +3352,14 @@ std::string NetworkGetPlayerPublicKeyHash(uint32_t id)
     return {};
 }
 
+void NetworkIncrementPlayerNumCommands(uint32_t playerIndex)
+{
+    auto& network = OpenRCT2::GetContext()->GetNetwork();
+    Guard::IndexInRange(playerIndex, network.player_list);
+
+    network.player_list[playerIndex]->IncrementNumCommands();
+}
+
 void NetworkAddPlayerMoneySpent(uint32_t index, money64 cost)
 {
     auto& network = OpenRCT2::GetContext()->GetNetwork();
@@ -4090,6 +4098,9 @@ std::string NetworkGetPlayerPublicKeyHash(uint32_t id)
 {
     return {};
 }
+void NetworkIncrementPlayerNumCommands(uint32_t playerIndex)
+{
+}
 void NetworkAddPlayerMoneySpent(uint32_t index, money64 cost)
 {
 }
diff --git a/src/openrct2/network/NetworkPlayer.cpp b/src/openrct2/network/NetworkPlayer.cpp
index 19459f829b..03783a1f42 100644
--- a/src/openrct2/network/NetworkPlayer.cpp
+++ b/src/openrct2/network/NetworkPlayer.cpp
@@ -36,11 +36,16 @@ void NetworkPlayer::Write(NetworkPacket& packet)
            << CommandsRan;
 }
 
-void NetworkPlayer::AddMoneySpent(money64 cost)
+void NetworkPlayer::IncrementNumCommands()
 {
-    MoneySpent += cost;
     CommandsRan++;
     WindowInvalidateByNumber(WindowClass::Player, Id);
 }
 
+void NetworkPlayer::AddMoneySpent(money64 cost)
+{
+    MoneySpent += cost;
+    WindowInvalidateByNumber(WindowClass::Player, Id);
+}
+
 #endif
diff --git a/src/openrct2/network/NetworkPlayer.h b/src/openrct2/network/NetworkPlayer.h
index 17d965429b..a292d36e7a 100644
--- a/src/openrct2/network/NetworkPlayer.h
+++ b/src/openrct2/network/NetworkPlayer.h
@@ -45,5 +45,6 @@ public:
 
     void Read(NetworkPacket& packet);
     void Write(NetworkPacket& packet);
+    void IncrementNumCommands();
     void AddMoneySpent(money64 cost);
 };
diff --git a/src/openrct2/network/network.h b/src/openrct2/network/network.h
index 988374fc3b..9d98e1c4a8 100644
--- a/src/openrct2/network/network.h
+++ b/src/openrct2/network/network.h
@@ -64,6 +64,7 @@ void NetworkFlush();
 [[nodiscard]] money64 NetworkGetPlayerMoneySpent(uint32_t index);
 [[nodiscard]] std::string NetworkGetPlayerIPAddress(uint32_t id);
 [[nodiscard]] std::string NetworkGetPlayerPublicKeyHash(uint32_t id);
+void NetworkIncrementPlayerNumCommands(uint32_t playerIndex);
 void NetworkAddPlayerMoneySpent(uint32_t index, money64 cost);
 [[nodiscard]] int32_t NetworkGetPlayerLastAction(uint32_t index, int32_t time);
 void NetworkSetPlayerLastAction(uint32_t index, GameCommand command);