In this article we will show you the best way of writing formal letter closing. When closing a formal letter, it is important to convey suitable measure of respect to the recipient. Therefore formal letter closing and signature shall reflect professional spirit as the rest of the formal letter. What is Complimentary Close? When closing a formal letter, it is custom to use so called Complimentary Close. Complimentary closing is the term preceding signature of the sender in a formal letter, or email. Within this term sender should show his/her respect, gratefulness and appreciation of the formal letter recipient. Every business and cover letter should contain complimentary close. However, please note that complementary close in both business and cover letter shall be quite