diff --git a/src/Postmark/PostmarkClientExtensions.cs b/src/Postmark/PostmarkClientExtensions.cs
index 507bb22..09775cb 100644
--- a/src/Postmark/PostmarkClientExtensions.cs
+++ b/src/Postmark/PostmarkClientExtensions.cs
@@ -24,7 +24,7 @@ public static class PostmarkClientExtensions
         /// <param name="textBody">The Plain Text Body to be used for the message, this may be null if HtmlBody is set.</param>
         /// <param name="htmlBody">The HTML Body to be used for the message, this may be null if TextBody is set.</param>
         /// <param name="headers">A collection of additional mail headers to send with the message.</param>
-        /// <param name="messageStream">The message stream used to send this message</param>
+        /// <param name="messageStream">The message stream used to send this message.</param>
         /// <returns>A <see cref = "PostmarkResponse" /> with details about the transaction.</returns>
         public static async Task<PostmarkResponse> SendMessageAsync(this PostmarkClient client,
             string from, string to, string subject, string textBody, string htmlBody,