In August 2018, Ethical Consumer viewed the 2017 annual accounts of Waterstones Booksellers Ltd, the company's ultimate European parent was Lynwood Investments CY Limited, registered in Cyprus. The ultimate parent was said to be Alpha Global (PTC) Limited, registered in the British Virgin Islands.
Both Cyprus and BVI were considered by Ethical Consumer to be tax havens at the time of writing.
In 2013 Waterstones website had this statement:
'Due to recent interest, we have been asked to clarify our position in regards to UK tax:
As a UK registered and domiciled business, Waterstones fulfils all its tax obligations. This will include both the payment and reporting of all necessary UK taxes, as set out under UK tax legislation.'
Ethical Consumer could find no such statement in 2018.
In 2013 Ethical Consumer did not find the above statement comprehensive enough, as it did not provide an explaination on why the its parent company was based in Bermuda. Furthermore, a parent company in a tax haven is regarded as a high risk company type for likely use of tax avoidance strategies under Ethical Consumer's rating system.
Waterstones therefore lost a whole mark under Anti-Social Finance.

Reference:

Annual accounts 2017 (2 August 2018)

In August 2018 Ethical Consumer viewed the most recent annual accounts of Waterstones Booksellers. According to this, the highest paid director received payments totalling £1,430,000 in 2017. Ethical Consumer considered payments over £1 million to be excessive. Waterstones therefore lost half a mark under Anti-Social Finance.

Reference:

Annual accounts 2017 (2 August 2018)