Certificate of authenticity
A certificate of authenticity, or COA, is a document, card or seal stating that an object is genuine. It is useful only when it can be traced to someone with the standing to say so: the maker, the artist, the artist's authorised office or a recognised expert.
Definition
A COA may accompany software, sports memorabilia, coins, luxury goods and art. Depending on the object, it usually names the item, gives a date of creation and a serial number, and carries the name or signature of the maker. It is usually supplied by the manufacturer, the artist or another approved body. For art, a good certificate states when and how the work was made, who was involved, its exact title and dimensions, and reference works that describe it, together with the qualifications and contact details of whoever wrote it.
Origin
In our reading, certificates matter most where many identical-looking objects need to be told apart: multiples, memorabilia, numbered editions. They also became a target for fraud. Fake certificates are widely acknowledged to accompany fake signed items, and in almost all such cases the paper is worthless and untraceable. In the United Kingdom, making or using a certificate to sell a fake can be an offence under section 7 of the Fraud Act 2006.
Some artists answer the problem with a single authorising office. Pest Control Office describes itself as the only source of certificates for Banksy. It issues them for paintings, prints and sculptures, but not for stickers, posters or anything that was not originally intended as a work of art, and it does not authenticate street works. It has stated that there were no Dismaland certificates and that Banksy has no licence agreements.
Key facts
| Abbreviation | COA |
|---|---|
| Usual contents | Item name, date, serial number, maker's name or signature |
| Good art COA | Medium, date, title, dimensions, references, and the issuer's qualifications and contact details |
| Who should issue | The maker, the artist or an approved body |
| Banksy | Pest Control Office is the sole source |
How to identify a useful one
- Who issued it. A certificate from the maker, the artist or the authorising office is evidence. A certificate from an unnamed or unreachable issuer is not.
- Contact details. A COA without full contact details for the issuer is of no value.
- Match to the object. The serial number, edition number or description should match the object in hand.
- Registers. Some offices keep a database; Pest Control Office will check a work against its records before a purchase if it already has a certificate.
- Our own description. We describe paperwork as it is: a maker's card, a gallery certificate, or none. We do not treat an independent letter as proof.
Where it appears in the collection
Paperwork from the maker is part of what we record. A fine silver Astro Boy birth commemorative medal of 2003, with cover and certificate, a Mattel Marie Antoinette Barbie with its certificate of authenticity, and a Martin Whatson Balloon print, edition of 250, with gallery certificate show three kinds. How paperwork bears on Banksy is read in our Banksy guide, and collecting habits in ten habits for collecting with Japonista. Numbered collectibles sit on our limited-edition collectibles shelf.
Related entries
- Edition number and artist's proof: matching the number to the paper.
- After-work: copies that make no claim to the artist's hand.
- Condition ranks: how we grade the object itself.
Sources
- Certificate of authenticity, encyclopaedia entry. wikipedia.org
- Pest Control Office, "Questions". pestcontroloffice.com
- Pest Control Office, "Check or register artwork". pestcontroloffice.com
- Pest Control Office, "Terms and Conditions of Submission". pestcontroloffice.com
Last reviewed 14 November 2026. The Japonista Curation and Concierge Team, Tokyo, Japan.