diff --git a/app/assets/javascripts/frontend/form-validation.js.coffee b/app/assets/javascripts/frontend/form-validation.js.coffee
index 973b5ccb8b..215143df0d 100644
--- a/app/assets/javascripts/frontend/form-validation.js.coffee
+++ b/app/assets/javascripts/frontend/form-validation.js.coffee
@@ -389,6 +389,30 @@ window.FormValidation =
       if errors
         @addErrorClass(question)
 
+  validateNumberByYears: (question) ->
+    inputCellsCounter = 0
+
+    for subquestion in question.find("input")
+      subq = $(subquestion)
+      qParent = subq.closest(".js-fy-entries")
+      errContainer = subq.closest(".span-financial")
+
+      shownQuestion = true
+      for conditional in $(subquestion).parents('.js-conditional-question')
+        if !$(conditional).hasClass('show-question')
+          shownQuestion = false
+
+      if shownQuestion
+        inputCellsCounter += 1
+
+        if not subq.val() and question.hasClass("question-required")
+          @logThis(question, "validateNumberByYears", "This field is required")
+          @appendMessage(errContainer, "This field is required")
+          @addErrorClass(question)
+          continue
+        else if not subq.val()
+          continue
+
   validateMoneyByYears: (question) ->
     inputCellsCounter = 0
 
@@ -660,6 +684,10 @@ window.FormValidation =
     if question.hasClass("question-matrix")
       @validateMatrix(question, triggeringElement)
 
+    if question.hasClass("question-number-by-years")
+      # console.log "validateNumberByYears"
+      @validateNumberByYears(question)
+
     if question.hasClass("question-money-by-years")
       # console.log "validateMoneyByYears"
       @validateMoneyByYears(question)
diff --git a/app/forms/award_years/v2024/innovation/innovation_step4.rb b/app/forms/award_years/v2024/innovation/innovation_step4.rb
index 3245beda7e..8d2f93ba5e 100644
--- a/app/forms/award_years/v2024/innovation/innovation_step4.rb
+++ b/app/forms/award_years/v2024/innovation/innovation_step4.rb
@@ -316,12 +316,14 @@ def innovation_step4
         by_years :units_sold, "Number of innovative units or contracts sold (if applicable)." do
           classes "sub-question"
           sub_ref "D 6.1"
+          required
           section :innovation_financials
           context %(
             <p>
               We recommend that you answer question C2.2 before proceeding with this and further questions, as this will automatically adjust the number of years you need to provide the figures for.
             </p>
-          )
+            <p>Enter '0' if you had none.</p>
+          ).squish
           type :number
           label ->(y) { "Financial year #{y}" }
 
@@ -334,7 +336,9 @@ def innovation_step4
         by_years :sales, "Sales of your innovative product/service (if applicable)." do
           classes "sub-question"
           sub_ref "D 6.2"
+          required
           section :innovation_financials
+          context %(<p>Enter '0' if you had none.</p>)
           type :money
           label ->(y) { "Financial year #{y}" }
 
@@ -347,6 +351,7 @@ def innovation_step4
         by_years :sales_exports, "Of which exports (if applicable)." do
           classes "sub-question"
           sub_ref "D 6.3"
+          required
           section :innovation_financials
           context %(<p>Enter '0' if you had none.</p>)
           type :money
@@ -361,6 +366,7 @@ def innovation_step4
         by_years :sales_royalties, "Of which royalties or licences (if applicable)." do
           classes "sub-question"
           sub_ref "D 6.4"
+          required
           section :innovation_financials
           context %(<p>Enter '0' if you had none.</p>)
           type :money
@@ -383,12 +389,14 @@ def innovation_step4
         by_years :avg_unit_price, "Average unit selling price or contract value (if applicable)." do
           classes "sub-question"
           sub_ref "D 6.6"
+          required
           section :innovation_financials
           context %(
             <p>
               If your innovation is a product, you must provide the unit price.
             </p>
-          )
+            <p>Enter '0' if you had none.</p>
+          ).squish
 
           type :money
           label ->(y) { "Financial year #{y}" }
@@ -409,10 +417,12 @@ def innovation_step4
         by_years :avg_unit_cost_self, "Direct cost, to you, of a single unit or contract (if applicable)." do
           classes "sub-question"
           sub_ref "D 6.8"
+          required
           section :innovation_financials
           context %(
             <p>If you haven't reached your latest year-end, use estimates to complete this question.</p>
-          )
+            <p>Enter '0' if you had none.</p>
+          ).squish
           type :money
           label ->(y) { "Financial year #{y}" }
           by_year_condition :innovation_was_launched_in_the_market, ->(v) { Utils::Date.within_range?(v, AwardYear.start_trading_between(2, 3)) }, 2, data: {value: AwardYear.start_trading_between(2, 3, minmax: true, format: true), type: :range, identifier: "2 to 3"}