According to the article this research was done by a company called Kantar Brandz. A wikipedia search on that company will generate this entry:
"The credibility of the Interbrand and BrandZ league tables have been cast into doubt by an article written in Marketing Week by Mark Ritson. The lack of clear definitions and valuation dates in the both companies methodology raise questions about the subjectivity involved in brand valuations. Being part of multinational advertising groups, Interbrand and Kantar Millward Brown also suffer from the risk of objectivity. Transparency and objectivity are two of the requirements of the ISO 10668 standard of monetary brand valuations."
And this article and this analysis company are the sole support this thread has for its claim.