diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1c3bce0..1ebe0a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,12 @@
 # VertexClient Changelog
 
 This file tracks all the changes (https://keepachangelog.com/en/1.0.0/) made to the client. This allows parsers such as Dependabot to provide a clean overview in pull requests.
+## [v0.12.0] - 2026-03-12
+
+#### Added
+
+- Add optional `posting_date` parameter to Invoice payload. When provided, sets `@postingDate` on the `InvoiceRequest` element for Vertex tax reporting period control. Omitting `posting_date` preserves existing behavior (no `@postingDate` attribute sent).
+
 ## [v0.11.3] - 2025-01-21
 
 #### Changed
diff --git a/README.md b/README.md
index f9624d4..669cfd9 100644
--- a/README.md
+++ b/README.md
@@ -128,6 +128,10 @@ VertexClient.invoice(
   # Vertex's Document Number is a unique referencial identifier for this invoice.
   document_number: "unique-identifier-1a43b",
 
+  # Optional posting date for controlling the Vertex tax reporting period (e.g. ship date).
+  # Defaults to documentDate when omitted.
+  posting_date: "2018-11-16",
+
   # ... All of the of the payload from quotation here ...
 )
 
diff --git a/lib/vertex_client/payloads/invoice.rb b/lib/vertex_client/payloads/invoice.rb
index 12816d7..3f934ac 100644
--- a/lib/vertex_client/payloads/invoice.rb
+++ b/lib/vertex_client/payloads/invoice.rb
@@ -11,10 +11,12 @@ def validate!
       end
 
       def body
-        super.merge({
-           :'@documentNumber' => params[:document_number],
-           :'@documentDate'   => params[:date]
-         })
+        b = super.merge({
+          :'@documentNumber' => params[:document_number],
+          :'@documentDate'   => params[:date]
+        })
+        b[:'@postingDate'] = params[:posting_date] if params[:posting_date].present?
+        b
       end
 
       def document_number_missing?
diff --git a/lib/vertex_client/version.rb b/lib/vertex_client/version.rb
index 08747e4..68c0311 100644
--- a/lib/vertex_client/version.rb
+++ b/lib/vertex_client/version.rb
@@ -1,3 +1,3 @@
 module VertexClient
-  VERSION = '0.11.3'
+  VERSION = '0.12.0'
 end
diff --git a/test/payloads/invoice_test.rb b/test/payloads/invoice_test.rb
index b13474a..cf5aece 100644
--- a/test/payloads/invoice_test.rb
+++ b/test/payloads/invoice_test.rb
@@ -16,6 +16,16 @@
     }), payload.body
   end
 
+  it 'includes @postingDate in body when posting_date is provided' do
+    working_quote_params[:posting_date] = '2026-03-12'
+    payload = VertexClient::Payload::Invoice.new(working_quote_params)
+    assert_equal '2026-03-12', payload.body[:'@postingDate']
+  end
+
+  it 'omits @postingDate from body when posting_date is not provided' do
+    assert_nil payload.body[:'@postingDate']
+  end
+
   it_supports_tax_only_adjustments(:working_quote_params)
 
   it 'supports sending is_tax_exempt to customer' do