diff --git a/zebra-consensus/src/block/check.rs b/zebra-consensus/src/block/check.rs
index 70340678326..e01df642d3c 100644
--- a/zebra-consensus/src/block/check.rs
+++ b/zebra-consensus/src/block/check.rs
@@ -261,7 +261,7 @@ pub fn miner_fees_are_valid(
         .map_err(|_| SubsidyError::SumOverflow)?;
 
     let should_allow_unclaimed_subsidy =
-        NetworkUpgrade::current(network, height) <= NetworkUpgrade::Nu5;
+        NetworkUpgrade::current(network, height) < NetworkUpgrade::Nu6;
 
     if if should_allow_unclaimed_subsidy {
         left > right
diff --git a/zebra-consensus/src/block/subsidy/funding_streams.rs b/zebra-consensus/src/block/subsidy/funding_streams.rs
index e4577a75ea5..9dd2bcf6122 100644
--- a/zebra-consensus/src/block/subsidy/funding_streams.rs
+++ b/zebra-consensus/src/block/subsidy/funding_streams.rs
@@ -35,7 +35,7 @@ pub fn funding_stream_values(
         let range = FUNDING_STREAM_HEIGHT_RANGES.get(&network.kind()).unwrap();
         if range.contains(&height) {
             let block_subsidy = block_subsidy(height, network)?;
-            let funding_stream_numerators = if current_network_upgrade <= Nu5 {
+            let funding_stream_numerators = if current_network_upgrade < Nu6 {
                 PRE_NU6_FUNDING_STREAM_RECEIVER_NUMERATORS.iter()
             } else {
                 POST_NU6_FUNDING_STREAM_RECEIVER_NUMERATORS.iter()
diff --git a/zebra-consensus/src/block/subsidy/general.rs b/zebra-consensus/src/block/subsidy/general.rs
index d7013c84ed4..a40620642a8 100644
--- a/zebra-consensus/src/block/subsidy/general.rs
+++ b/zebra-consensus/src/block/subsidy/general.rs
@@ -7,7 +7,10 @@ use std::collections::HashSet;
 use zebra_chain::{
     amount::{Amount, Error, NonNegative},
     block::{Height, HeightDiff},
-    parameters::{Network, NetworkUpgrade::*},
+    parameters::{
+        Network,
+        NetworkUpgrade::{self, *},
+    },
     transaction::Transaction,
 };
 
@@ -108,6 +111,40 @@ pub fn miner_subsidy(height: Height, network: &Network) -> Result<Amount<NonNega
     block_subsidy(height, network)? - total_funding_stream_amount?
 }
 
+/// Lockbox funding stream total input value for a block height.
+///
+/// Assumes a constant funding stream amount per block.
+// TODO: Cache the lockbox value balance in zebra-state (will be required for tracking lockbox
+//       value balance after ZSF ZIPs or after a ZIP for spending from the deferred pool)
+#[allow(dead_code)]
+fn lockbox_input_value(network: &Network, height: Height) -> Amount<NonNegative> {
+    let Some(nu6_activation_height) = NetworkUpgrade::Nu6.activation_height(network) else {
+        return Amount::zero();
+    };
+
+    let &deferred_amount_per_block = funding_stream_values(nu6_activation_height, network)
+        .expect("we always expect a funding stream hashmap response even if empty")
+        .get(&FundingStreamReceiver::Deferred)
+        .expect("we expect a lockbox funding stream after NU5");
+
+    let funding_stream_height_range = FUNDING_STREAM_HEIGHT_RANGES
+        .get(&network.kind())
+        .expect("must have funding stream height range on all networks");
+
+    // `min(height, last_height_with_deferred_pool_contribution) - (nu6_activation_height - 1)`,
+    // funding stream height range end bound is not incremented since it's an exclusive end bound
+    let num_blocks_with_lockbox_output = height
+        .next()
+        .expect("should be a valid height")
+        .min(funding_stream_height_range.end)
+        - nu6_activation_height;
+
+    (deferred_amount_per_block
+        * u64::try_from(num_blocks_with_lockbox_output)
+            .expect("num blocks with lockbox funding stream should fit in u64"))
+    .expect("lockbox input value should fit in Amount")
+}
+
 /// Returns all output amounts in `Transaction`.
 pub fn output_amounts(transaction: &Transaction) -> HashSet<Amount<NonNegative>> {
     transaction