DUBLIN, April 4, 2013 /PRNewswire/ -- The valuations placed on German discounters Aldi and Lidl, by two of the world's biggest brand valuation companies, has been brought into question by ESM, the leading pan-European grocery trade magazine. In the latest issue of ESM, the magazine looks at the vast differences in the valuations placed on some of the world's leading FMCG and retail brands by valuation companies Interbrand and BrandZ, in a piece entitled 'Valuing Your Brand - What's $100 Million Between Friends?'. The companies' 2012 reports saw BrandZ value Aldi at $9.3 billion, while Interbrand rated it at $3.1 billion, bringing it down to $2.9 billion in its 2013 listings. Lidl was valued at $4.6 billion by BrandZ in 2012, while Interbrand ranked the brand's worth as being only $1.4 billion, bumping it up to $1.5 billion in this year's report. ESM says that the uber-private nature of the German discounters make it impossible to access the information upon which they could be valued, calling into question the validity of the assessments of both Interbrand and BrandZ. ESM also queries the vast difference in the valuations of Tesco, with BrandZ giving the Britain-based retailer a significantly higher rating at $18.2 billion, compared to Interbrand's $11 billion. However, ESM's biggest query is with the $100 million discrepancy in the valuations of Walmart. Valued at $139.1 billion by Interbrand in 2012, BrandZ reckoned the world's largest supermarket retailer was worth only $34.4 billion. ESM spoke to the companies about their differing valuations, highlighting their individual methodologies, but feels that the vast differences aren't justified and poses the question to brand owners - what is your brand really worth?