The two New York-headquartered firms head a list of about 40 firms that are rated for copyright work nationally and in four regions in the US.
The survey is the second time the magazine has published rankings of the leading firms for copyright work.
In Europe, Bird and Bird, Freshfields Bruckhaus Deringer and Lovells each feature in the top tier in two countries.
Bird & Bird is top rated, along with Olswang, in the UK. It is also in the top tier in Italy and, as ATMD Bird & Bird Singapore.
Freshfields is among four firms in the top tier in France and five in the Netherlands. Lovells is top rated in the Netherlands and Germany.
The second annual copyright survey ranks the leading firms in 19 jurisdictions, and follows the publication of the rankings of leading firms for patent and trade mark work in February and March.
The results are based on research carried out by telephone, email and face-to-face interviews with IP practitioners over a period of about six months, by a team of researchers in London, New York and Hong Kong.
More details about the IP survey are available on the dedicated pages on managingip.com (access restricted to Managing IP subscribers).
