diff --git a/app/admin/applications.rb b/app/admin/applications.rb
index 3e43eb7..3bc5eff 100644
--- a/app/admin/applications.rb
+++ b/app/admin/applications.rb
@@ -28,18 +28,34 @@
   filter :subscription, as: :select
   filter :conf_year, as: :select
 
+  controller do
+    before_action :load_index_batch_data, only: [:index]
+
+    def scoped_collection
+      end_of_association_chain.includes(:partner_registration)
+    end
+
+    private
+
+    def load_index_batch_data
+      raw = Payment
+        .where(transaction_status: '1')
+        .group(:user_id, :conf_year)
+        .sum(Arel.sql("total_amount::numeric"))
+      # Normalize keys to [Integer, Integer] so lookup matches regardless of DB return type
+      @payments_total_by_user_and_year = raw.transform_keys { |k| [k[0].to_i, k[1].to_i] }
+      @lodgings_by_description = Lodging.all.index_by(&:description)
+    end
+  end
+
   index do
     selectable_column
     actions
     column :offer_status
     column "Balance Due" do |application|
-      users_current_payments = Payment.where(user_id: application.user_id, conf_year: application.conf_year)
-      ttl_paid = Payment.where(user_id: application.user_id, conf_year: application.conf_year, transaction_status: '1').pluck(:total_amount).map(&:to_f).sum / 100
-      cost_lodging = Lodging.find_by(description: application.lodging_selection).cost.to_f
-      cost_partner = application.partner_registration.cost.to_f
-      total_cost = cost_lodging + cost_partner
-      balance_due = total_cost - ttl_paid
-      number_to_currency(balance_due)
+      payments_totals = controller.instance_variable_get(:@payments_total_by_user_and_year) || {}
+      lodgings_by_desc = controller.instance_variable_get(:@lodgings_by_description) || {}
+      number_to_currency(application.balance_due_with_batch(payments_totals: payments_totals, lodgings_by_desc: lodgings_by_desc))
     end
     column :first_name
     column :last_name
@@ -49,16 +65,18 @@
     column :workshop_selection3
     column :lodging_selection
     column "partner_registration_id" do |application|
-      application.partner_registration.display_name
+      application.partner_registration&.display_name
     end
     column :birth_year
   end
 
   show do
 
-    users_current_payments = Payment.where(user_id: application.user_id, conf_year: application.conf_year) # Payment.current_conference_payments.where(user_id: application.user_id)
     ttl_paid = Payment.where(user_id: application.user_id, conf_year: application.conf_year, transaction_status: '1').pluck(:total_amount).map(&:to_f).sum / 100
     cost_lodging = Lodging.find_by(description: application.lodging_selection).cost.to_f
+    if application.partner_registration.nil?
+      raise "Partner registration is missing for this application (id=#{application.id}); cannot compute balance. Fix data and retry."
+    end
     cost_partner = application.partner_registration.cost.to_f
     total_cost = cost_lodging + cost_partner
     balance_due = total_cost - ttl_paid
@@ -66,14 +84,14 @@
       table_for application.user.payments.where(conf_year: application.conf_year) do #application.user.payments.current_conference_payments
         column(:id) { |aid| link_to(aid.id, admin_payment_path(aid.id)) }
         column(:account_type) { |atype| atype.account_type.titleize }
-        column(:transaction_type) 
+        column(:transaction_type)
         column(:transaction_date) {|td| Date.parse(td.transaction_date) }
         column(:total_amount) { |ta|  number_to_currency(ta.total_amount.to_f / 100) }
       end
       text_node link_to("[Add Manual Payment]", new_admin_payment_path(:user_id => application))
     end
 
-    
+
     attributes_table do
       row :user
       row :conf_year
@@ -100,7 +118,7 @@
       row :workshop_selection3
       row :lodging_selection
       row "partner_registration_id" do |app|
-        app.partner_registration.display_name
+        app.partner_registration&.display_name
       end
       row :partner_first_name
       row :partner_last_name
@@ -161,7 +179,9 @@
     column :lottery_position
     column :offer_status
     column "Balance Due" do |application|
-      users_current_payments = Payment.current_conference_payments.where(user_id: application.user_id)
+      if application.partner_registration.nil?
+        raise "Application #{application.id}: partner_registration is missing; cannot compute balance for CSV export."
+      end
       ttl_paid = Payment.current_conference_payments.where(user_id: application.user_id, transaction_status: '1').pluck(:total_amount).map(&:to_f).sum / 100
       cost_lodging = Lodging.find_by(description: application.lodging_selection).cost.to_f
       cost_partner = application.partner_registration.cost.to_f
@@ -178,7 +198,7 @@
     column :workshop_selection3
     column :lodging_selection
     column "partner_registration_id" do |app|
-      app.partner_registration.display_name
+      app.partner_registration&.display_name
     end
     column :birth_year
     column :street
diff --git a/app/admin/dashboard.rb b/app/admin/dashboard.rb
index 9826543..f736280 100644
--- a/app/admin/dashboard.rb
+++ b/app/admin/dashboard.rb
@@ -45,10 +45,14 @@
       end
       column do
         panel "#{ApplicationSetting.get_current_app_year} Applicants who accepted their offer (#{Application.application_accepted.count})" do
-          table_for Application.application_accepted.sort.reverse do
+          applications = Application.application_accepted.includes(:partner_registration).sort.reverse
+          raw_payments = Payment.where(transaction_status: '1').group(:user_id, :conf_year).sum(Arel.sql("total_amount::numeric"))
+          payments_totals = raw_payments.transform_keys { |k| [k[0].to_i, k[1].to_i] }
+          lodgings_by_desc = Lodging.all.index_by(&:description)
+          table_for applications do
             column("Applicant") { |u| link_to(u.display_name, admin_application_path(u.id)) }
             column("Offer Date") { |od| od.offer_status_date }
-            column("Balance Due") { |a| number_to_currency a.balance_due }
+            column("Balance Due") { |a| number_to_currency(a.balance_due_with_batch(payments_totals: payments_totals, lodgings_by_desc: lodgings_by_desc)) }
           end
         end
       end
diff --git a/app/models/application.rb b/app/models/application.rb
index 5b15d72..49e40f5 100644
--- a/app/models/application.rb
+++ b/app/models/application.rb
@@ -87,7 +87,7 @@ def total_user_has_paid
   end
 
   def lodging_cost
-    Lodging.find_by(description: self.lodging_selection).cost.to_f 
+    Lodging.find_by(description: self.lodging_selection).cost.to_f
   end
 
   def partner_registration_cost
@@ -102,6 +102,22 @@ def balance_due
     total_cost - total_user_has_paid
   end
 
+  # Balance due in dollars using preloaded data (avoids N+1). Payments total is in cents.
+  # Returns a rounded float suitable for number_to_currency.
+  # Raises if partner_registration or lodging is missing (data integrity: do not treat missing as $0).
+  def balance_due_with_batch(payments_totals:, lodgings_by_desc:)
+    raise "Application #{id}: partner_registration is missing; cannot compute balance." if partner_registration.nil?
+    lodging = lodgings_by_desc[lodging_selection]
+    raise "Application #{id}: lodging not found for selection '#{lodging_selection}'; cannot compute balance." if lodging.nil?
+    key = [user_id.to_i, conf_year.to_i]
+    ttl_paid_cents = (payments_totals[key] || 0).to_f
+    ttl_paid_dollars = ttl_paid_cents / 100
+    cost_lodging = lodging.cost.to_f
+    cost_partner = partner_registration.cost.to_f
+    total_cost = cost_lodging + cost_partner
+    (total_cost - ttl_paid_dollars).round(2)
+  end
+
   def first_workshop_instructor
     Workshop.find(workshop_selection1).instructor
   end
diff --git a/spec/models/application_spec.rb b/spec/models/application_spec.rb
index 84fed9f..c1aa56b 100644
--- a/spec/models/application_spec.rb
+++ b/spec/models/application_spec.rb
@@ -191,6 +191,50 @@
       end
     end
 
+    describe '#balance_due_with_batch' do
+      it 'returns balance as total cost minus paid (payments in cents), rounded to 2 decimals' do
+        app = build(:application, user_id: 100, conf_year: 2026, lodging_selection: 'Standard')
+        allow(app).to receive(:partner_registration).and_return(double('PartnerRegistration', cost: 50.0))
+        payments_totals = { [100, 2026] => 10_000 }  # $100 in cents
+        lodgings_by_desc = { 'Standard' => double('Lodging', cost: 100.0) }
+        expect(app.balance_due_with_batch(payments_totals: payments_totals, lodgings_by_desc: lodgings_by_desc)).to eq(50.0)
+      end
+
+      it 'uses 0 for paid when key is missing in payments_totals' do
+        app = build(:application, user_id: 100, conf_year: 2026, lodging_selection: 'Standard')
+        allow(app).to receive(:partner_registration).and_return(double('PartnerRegistration', cost: 50.0))
+        payments_totals = {}
+        lodgings_by_desc = { 'Standard' => double('Lodging', cost: 100.0) }
+        expect(app.balance_due_with_batch(payments_totals: payments_totals, lodgings_by_desc: lodgings_by_desc)).to eq(150.0)
+      end
+
+      it 'returns negative balance when paid exceeds total cost (overpayment)' do
+        app = build(:application, user_id: 100, conf_year: 2026, lodging_selection: 'Standard')
+        allow(app).to receive(:partner_registration).and_return(double('PartnerRegistration', cost: 50.0))
+        payments_totals = { [100, 2026] => 20_000 }  # $200 in cents
+        lodgings_by_desc = { 'Standard' => double('Lodging', cost: 100.0) }
+        expect(app.balance_due_with_batch(payments_totals: payments_totals, lodgings_by_desc: lodgings_by_desc)).to eq(-50.0)
+      end
+
+      it 'raises when partner_registration is missing (do not treat as $0)' do
+        app = build(:application, user_id: 100, conf_year: 2026, lodging_selection: 'Unknown')
+        allow(app).to receive(:partner_registration).and_return(nil)
+        payments_totals = { [100, 2026] => 0 }
+        lodgings_by_desc = {}
+        expect { app.balance_due_with_batch(payments_totals: payments_totals, lodgings_by_desc: lodgings_by_desc) }
+          .to raise_error(/partner_registration is missing/)
+      end
+
+      it 'raises when lodging is not found in lodgings_by_desc (do not treat as $0)' do
+        app = build(:application, user_id: 100, conf_year: 2026, lodging_selection: 'DeletedOrInvalidLodging')
+        allow(app).to receive(:partner_registration).and_return(double('PartnerRegistration', cost: 50.0))
+        payments_totals = { [100, 2026] => 0 }
+        lodgings_by_desc = { 'Standard' => double('Lodging', cost: 100.0) }
+        expect { app.balance_due_with_batch(payments_totals: payments_totals, lodgings_by_desc: lodgings_by_desc) }
+          .to raise_error(/lodging not found for selection 'DeletedOrInvalidLodging'/)
+      end
+    end
+
     describe '#first_workshop_instructor' do
       it 'returns the instructor of the first workshop' do
         workshop = double("Workshop", instructor: "John Smith")
diff --git a/spec/requests/admin_applications_spec.rb b/spec/requests/admin_applications_spec.rb
new file mode 100644
index 0000000..23aee5d
--- /dev/null
+++ b/spec/requests/admin_applications_spec.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'Admin Applications index', type: :request, no_application_mock: true do
+  let(:admin_user) { create(:admin_user) }
+
+  describe 'GET /admin/applications' do
+    context 'when admin is not signed in' do
+      it 'redirects to admin sign in page' do
+        get admin_applications_path
+        expect(response).to redirect_to(new_admin_user_session_path)
+      end
+    end
+
+    context 'when admin is signed in' do
+      before { sign_in admin_user }
+
+      it 'renders successfully with default scope' do
+        get admin_applications_path
+        expect(response).to be_successful
+      end
+
+      it 'renders successfully with scope=all (batch data loaded)' do
+        get admin_applications_path, params: { scope: 'all' }
+        expect(response).to be_successful
+      end
+
+      it 'includes Balance Due column when applications exist' do
+        create(:lodging, description: 'Standard')
+        create(:application, lodging_selection: 'Standard')
+        get admin_applications_path
+        expect(response).to be_successful
+        expect(response.body).to include('Balance Due')
+      end
+    end
+  end
+end
diff --git a/spec/support/application_mock.rb b/spec/support/application_mock.rb
index ed7936b..fcd2fec 100644
--- a/spec/support/application_mock.rb
+++ b/spec/support/application_mock.rb
@@ -1,5 +1,8 @@
 RSpec.configure do |config|
   config.before(:each, type: :request) do
+    # Skip mock when testing admin applications index (needs real ActiveRecord chain)
+    next if RSpec.current_example.metadata[:no_application_mock]
+
     # Create a mock for Application.active_conference_applications
     mock_active_applications = double("ActiveApplications")
 
diff --git a/yarn.lock b/yarn.lock
index 5937ba5..e8f2440 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -141,9 +141,9 @@
     "@rails/actioncable" "^7.0"
 
 "@hotwired/turbo@^8.0.2":
-  version "8.0.2"
-  resolved "https://registry.yarnpkg.com/@hotwired/turbo/-/turbo-8.0.2.tgz#c31cdadfe66b98983066a94073b26fc7e15835f0"
-  integrity sha512-3K6QZkwWfosAV8zuM5bY+kKF02jp1lMQGsWfSE6wXdZBRBP3ah+Vj26YNqYtkEomBwRWA0QKhZgyJP7xOQkVEg==
+  version "8.0.21"
+  resolved "https://registry.yarnpkg.com/@hotwired/turbo/-/turbo-8.0.21.tgz#a3e80c01d70048200f64bbe3582b84f9bfac034e"
+  integrity sha512-fJTv3JnzFHeDxBb23esZSOhT4r142xf5o3lKMFMvzPC6AllkqbBKk5Yb31UZhtIsKQCwmO/pUQrtTUlYl5CHAQ==
 
 "@nodelib/fs.scandir@2.1.5":
   version "2.1.5"