diff --git a/app/models/rule/action_executor/set_transaction_merchant.rb b/app/models/rule/action_executor/set_transaction_merchant.rb
new file mode 100644
index 00000000..492ece52
--- /dev/null
+++ b/app/models/rule/action_executor/set_transaction_merchant.rb
@@ -0,0 +1,30 @@
+class Rule::ActionExecutor::SetTransactionMerchant < Rule::ActionExecutor
+  def type
+    "select"
+  end
+
+  def options
+    family.merchants.pluck(:name, :id)
+  end
+
+  def execute(transaction_scope, value: nil, ignore_attribute_locks: false)
+    merchant = family.merchants.find_by_id(value)
+    return unless merchant
+
+    scope = transaction_scope
+    unless ignore_attribute_locks
+      scope = scope.enrichable(:merchant_id)
+    end
+
+    scope.each do |txn|
+      Rule.transaction do
+        txn.log_enrichment!(
+          attribute_name: "merchant_id",
+          attribute_value: merchant.id,
+          source: "rule"
+        )
+        txn.update!(merchant: merchant)
+      end
+    end
+  end
+end
diff --git a/app/models/rule/registry/transaction_resource.rb b/app/models/rule/registry/transaction_resource.rb
index 1bcdf8a7..628d8cde 100644
--- a/app/models/rule/registry/transaction_resource.rb
+++ b/app/models/rule/registry/transaction_resource.rb
@@ -14,7 +14,8 @@ class Rule::Registry::TransactionResource < Rule::Registry
   def action_executors
     enabled_executors = [
       Rule::ActionExecutor::SetTransactionCategory.new(rule),
-      Rule::ActionExecutor::SetTransactionTags.new(rule)
+      Rule::ActionExecutor::SetTransactionTags.new(rule),
+      Rule::ActionExecutor::SetTransactionMerchant.new(rule)
     ]
 
     if ai_enabled?
diff --git a/test/models/rule/action_test.rb b/test/models/rule/action_test.rb
index 6cab0bd9..61ee6425 100644
--- a/test/models/rule/action_test.rb
+++ b/test/models/rule/action_test.rb
@@ -58,4 +58,25 @@ class Rule::ActionTest < ActiveSupport::TestCase
       assert_equal [ tag ], transaction.reload.tags
     end
   end
+
+  test "set_transaction_merchant" do
+    merchant = @family.merchants.create!(name: "Rule test merchant")
+
+    # Does not modify transactions that are locked (user edited them)
+    @txn1.lock!(:merchant_id)
+
+    action = Rule::Action.new(
+      rule: @transaction_rule,
+      action_type: "set_transaction_merchant",
+      value: merchant.id
+    )
+
+    action.apply(@rule_scope)
+
+    assert_not_equal merchant.id, @txn1.reload.merchant_id
+
+    [ @txn2, @txn3 ].each do |transaction|
+      assert_equal merchant.id, transaction.reload.merchant_id
+    end
+  end
 end