COA is an abbreviation for Certificate of Authenticity. When a seller wants a guarantee that an item is authentic, a COA is generally offered on items such as sports memorabilia and autographs.
Unfortunately a COA can also be faked. Anyone can print up a realistic looking COA (Certificate of Authenticity). So the question is, can we get a COA for that COA?
Tip: Only trust COAs that are from reputable companies and have a money back guarantee.
A similar term used is LOA -- Letter of Authenticity