That's subjective. In America companies tend to be referred to as singular entities, but in the UK they would be referred to as plural. Neither is wrong, just different idioms.
> In British English it’s absolutely fine to treat most collective nouns as either singular or plural – you can say my husband’s family is very religious or my husband’s family are very religious.
http://itre.cis.upenn.edu/~myl/languagelog/archives/001874.h...
etc.
With something like collective nouns it's probably wrong to make blanket statements about correct and incorrect, even if you're a prescriptivist not descriptivist.
EDIT: And while I love (but am hopeless with) English usage this is the least interesting bit of the submitted article.
Note while 'just' a style guide, The Economist - like me - seems (note not 'seem' ;)) not to consider "Tesco" _et al_ to be collective nouns _per se_.
> A government, a party, a company (whether Tesco or Marks
> and Spencer) and a partnership (Skidmore, Owings &
> Merrill) are all **it** and take a singular verb.