diff --git a/src/bench/coin_selection.cpp b/src/bench/coin_selection.cpp
--- a/src/bench/coin_selection.cpp
+++ b/src/bench/coin_selection.cpp
@@ -12,21 +12,15 @@
 #include <set>
 
 static void addCoin(const Amount nValue, const CWallet &wallet,
-                    std::vector<OutputGroup> &groups) {
-    int nInput = 0;
-
+                    std::vector<std::unique_ptr<CWalletTx>> &wtxs) {
     static int nextLockTime = 0;
     CMutableTransaction tx;
     // so all transactions get different hashes
     tx.nLockTime = nextLockTime++;
-    tx.vout.resize(nInput + 1);
-    tx.vout[nInput].nValue = nValue;
-    CWalletTx *wtx = new CWalletTx(&wallet, MakeTransactionRef(std::move(tx)));
-
-    int nAge = 6 * 24;
-    COutput output(wtx, nInput, nAge, true /* spendable */, true /* solvable */,
-                   true /* safe */);
-    groups.emplace_back(output.GetInputCoin(), 6, false, 0, 0);
+    tx.vout.resize(1);
+    tx.vout[0].nValue = nValue;
+    wtxs.push_back(std::make_unique<CWalletTx>(
+        &wallet, MakeTransactionRef(std::move(tx))));
 }
 
 // Simple benchmark for wallet coin selection. Note that it maybe be necessary
@@ -42,15 +36,23 @@
     auto chain = interfaces::MakeChain();
     const CWallet wallet(Params(), *chain, WalletLocation(),
                          WalletDatabase::CreateDummy());
-
+    std::vector<std::unique_ptr<CWalletTx>> wtxs;
     LOCK(wallet.cs_wallet);
 
     // Add coins.
-    std::vector<OutputGroup> groups;
     for (int i = 0; i < 1000; ++i) {
-        addCoin(1000 * COIN, wallet, groups);
+        addCoin(1000 * COIN, wallet, wtxs);
+    }
+    addCoin(3 * COIN, wallet, wtxs);
+
+    // Create groups
+    std::vector<OutputGroup> groups;
+    for (const auto &wtx : wtxs) {
+        COutput output(wtx.get(), 0 /* iIn */, 6 * 24 /* nDepthIn */,
+                       true /* spendable */, true /* solvable */,
+                       true /* safe */);
+        groups.emplace_back(output.GetInputCoin(), 6, false, 0, 0);
     }
-    addCoin(3 * COIN, wallet, groups);
 
     const CoinEligibilityFilter filter_standard(1, 6, 0);
     const CoinSelectionParams coin_selection_params(