Banksy trademark 'at risk' after street artist loses legal battle | Banksy | The Guardian

So is use of a nom de plume fatal to copyright protection?  Fixed in a tangible medium of expression seems to be all you need.

Is the trademark the name Banksy?

Banksy trademark 'at risk' after street artist loses legal battle | Banksy | The Guardian

Banksy’s trademark may be at risk after the street artist lost a case that an EU panel said was brought in bad faith and was undermined by a gift shop he set up in London last year.

Banksy lost the case against a greeting card company, Full Colour Black, which argued it should be able to use an image of the Flower Thrower stencil mural, which he painted in Jerusalem, because of the artist’s anonymity.

In 2014, Banksy’s representatives, Pest Control Office, successfully applied for an EU trademark of the Flower Thrower, but this week that was overturned after a two-year dispute.

The European Union Intellectual Property Office (EUIPO) panel said it ruled against the artist because he could not be identified as the unquestionable owner of such works because his identity remained hidden.