diff --git a/backend/models/src/main/java/de/cotto/bitbook/backend/model/Transaction.java b/backend/models/src/main/java/de/cotto/bitbook/backend/model/Transaction.java
index 3f331925..2192409c 100644
--- a/backend/models/src/main/java/de/cotto/bitbook/backend/model/Transaction.java
+++ b/backend/models/src/main/java/de/cotto/bitbook/backend/model/Transaction.java
@@ -41,7 +41,7 @@ public Transaction(
         this.time = time.withNano(0);
         this.fees = fees;
         this.inputs = inputs.stream().filter(input -> input.getValue().satoshis() > 0).collect(toList());
-        this.outputs = outputs.stream().filter(output -> output.getValue().satoshis() > 0).collect(toList());
+        this.outputs = new ArrayList<>(outputs);
         this.chain = chain;
         validateCoinsSum(hash, fees, inputs, outputs);
     }
diff --git a/backend/models/src/test/java/de/cotto/bitbook/backend/model/TransactionTest.java b/backend/models/src/test/java/de/cotto/bitbook/backend/model/TransactionTest.java
index af31316f..cdde10d7 100644
--- a/backend/models/src/test/java/de/cotto/bitbook/backend/model/TransactionTest.java
+++ b/backend/models/src/test/java/de/cotto/bitbook/backend/model/TransactionTest.java
@@ -68,7 +68,7 @@ void forCoinbase() {
                 List.of(OUTPUT_1, OUTPUT_2, new Output(Coins.NONE, new Address("xxx"))),
                 BTC
         );
-        assertThat(coinbaseTransaction.getOutputs()).hasSize(2);
+        assertThat(coinbaseTransaction.getOutputs()).hasSize(3);
     }
 
     @Test
@@ -259,7 +259,9 @@ void getOutputs() {
     }
 
     @Test
-    void ignoresEmptyOutputs() {
+    void includes_empty_outputs() {
+        // Even though outputs not spending anything, they count when considering the output index.
+        // As the output index is used to identify lightning network channels, empty outputs must not be ignored.
         List<Output> outputs = List.of(
                 Output.EMPTY,
                 new Output(Coins.NONE, new Address("xx")),
@@ -268,7 +270,9 @@ void ignoresEmptyOutputs() {
         );
         Transaction transaction =
                 new Transaction(TRANSACTION_HASH, BLOCK_HEIGHT, DATE_TIME, FEES, TRANSACTION.getInputs(), outputs, BTC);
-        assertThat(transaction.getOutputs()).isEqualTo(TRANSACTION.getOutputs());
+        assertThat(transaction.getOutputs())
+                .containsAll(TRANSACTION.getOutputs())
+                .hasSize(4);
     }
 
     @Test
@@ -345,4 +349,4 @@ private Transaction getTransaction(Coins inFromAddress, Coins outToAddress2) {
                 BTC
         );
     }
-}
\ No newline at end of file
+}
diff --git a/backend/provider/blockchair/src/test/java/de/cotto/bitbook/backend/transaction/blockchair/BlockchairTransactionDtoTest.java b/backend/provider/blockchair/src/test/java/de/cotto/bitbook/backend/transaction/blockchair/BlockchairTransactionDtoTest.java
index 226eec6b..008aa33a 100644
--- a/backend/provider/blockchair/src/test/java/de/cotto/bitbook/backend/transaction/blockchair/BlockchairTransactionDtoTest.java
+++ b/backend/provider/blockchair/src/test/java/de/cotto/bitbook/backend/transaction/blockchair/BlockchairTransactionDtoTest.java
@@ -192,6 +192,6 @@ void deserialization_zero_output_with_d_address() throws Exception {
                 }""";
         BlockchairTransactionDto blockchairTransactionDto =
                 objectMapper.readValue(json, BlockchairTransactionDto.class);
-        assertThat(blockchairTransactionDto.toModel(BTC).getOutputs()).isEmpty();
+        assertThat(blockchairTransactionDto.toModel(BTC).getOutputs()).hasSize(1);
     }
-}
\ No newline at end of file
+}
diff --git a/backend/provider/btccom/src/test/java/de/cotto/bitbook/backend/transaction/btccom/BtcComTransactionDtoTest.java b/backend/provider/btccom/src/test/java/de/cotto/bitbook/backend/transaction/btccom/BtcComTransactionDtoTest.java
index 4fee4146..568d592a 100644
--- a/backend/provider/btccom/src/test/java/de/cotto/bitbook/backend/transaction/btccom/BtcComTransactionDtoTest.java
+++ b/backend/provider/btccom/src/test/java/de/cotto/bitbook/backend/transaction/btccom/BtcComTransactionDtoTest.java
@@ -354,6 +354,6 @@ void deserialization_zero_output_with_null_data() throws Exception {
                 }""";
         BtcComTransactionDto btcComTransactionDto =
                 objectMapper.readValue(json, BtcComTransactionDto.class);
-        assertThat(btcComTransactionDto.toModel(BTC).getOutputs()).isEmpty();
+        assertThat(btcComTransactionDto.toModel(BTC).getOutputs()).hasSize(1);
     }
-}
\ No newline at end of file
+}