In business letters nowadays, there are two styles of punctuation being used. One is mixed punctuation and the other is open punctuation. Mixed punctuation requires a colon to follow the opening salutation and comma to end the complementary close. However in open punctuation, both the colon and the comma can be given a miss. This style is popular in the United States and is also gaining popularity in Europe.
Open punctuation is a relatively new concept in English grammar and has been popularised by the use of computers. Open punctuation means a minimal use of punctuation throughout the body of the letter. Due to the ability to review spelling and grammar content electronically, the open punctuation style has become more and more accepted.
Punctuation in the Address Line
Traditionally, after each address line, a comma is used. However, according to Purdue Online Writing Lab, open punctuation has become increasingly popular in full block business letters. In this style, there is usually no punctuation at the end of the address lines. Each line of the address can be left without punctuation. However, if you like the traditional style better, you can use a comma on each line of address except for the last one, which is the more modern style of writing addresses on formal letters.
About Punctuation in an U.S. Business Letter
The traditional United States rules for writing business letters state that a colon should be used after the salutation greeting of the business letter and a comma should be used after the complementary close. This kind of punctuation is known as mixed punctuation. However, open punctuation is becoming increasingly popular and is fast becoming a norm, according to Savvy Business Correspondence.
About Punctuation in an European Business Letter
In Europe, a comma is traditionally used both after the initial salutation greeting as well as the complementary close in all business letters. However, due to the increasing popularity of open punctuation in the United States, open punctuation has started to be accepted in Europe as well.
Punctuation in the Body
For block formats, or formats in which each line begins from the left margin, the layout has been modified slightly. The body of the letter is kept justified and a blank line is left between each paragraph. The punctuation in the body of the letter should be followed as the grammar and syntax dictate. The context of the body remains largely the same, with an opening statement of purpose and subsequent paragraphs stating the background and supporting information. Here, open punctuation is not used.
Newer versions of Microsoft Office have business letter templates where the writing style uses mostly open punctuation. According to Purdue Online Writing Lab, Microsoft Office 2000 offers three types of business letter wizards which can be used to write the letters of your choice. All of these follow different styles and rules of punctuation.