The Top 10 Global Brands ranking is based on brand value, as opposed to other rankings which might rely on surveys.

Interbrand has several criteria which must be met before a company can even be considered for Interbrand's ranking.

• There must be substantial publicly available financial data
• The brand must have at least one-third of revenues outside of its country-of-origin
• The brand must be a market-facing brand
• The Economic Value Added (EVA) must be positive
• The brand must not have a purely B2B single audience with no wider public profile and awareness

Despite what you might think, this criteria excludes Walmart, which according to Interbrand, is not sufficiently global because "it does business in some international markets but not under the Walmart brand."

Privately held companies such as Mars are also excluded from top 10 global brands ranking.

Their methodology for ranking is described on page 14 of this year's report (.PDF).

The Interbrand method for valuing brands is a proven, straightforward, and profound formula that examines brands through the lens of financial strength, importance in driving consumer selection, and the likelihood of ongoing branded revenue. Our method evaluates brands much like analysts would value any other asset: on the basis of how much they’re likely to earn in the future.

There are three core components to our proprietary method:

Financial Analysis

Our approach to valuation starts by forecasting the current and future revenue specifically attributable to the branded products.

Role of Brand Analysis

A measure of how the brand influences customer demand at the point of purchase is applied to the economic earnings to arrive at Branded Earnings.

Brand Strength Score

This is a benchmark of the brand’s ability to secure ongoing customer demand (loyalty, repurchase and retention) and thus sustain future earnings, translating branded earnings into net present value. This assessment is a structured way of determining the specific risk to the strength of the brand. We compare the brand against common factors of brand strength, such as: market position, customer franchise, image, and support.

The brand values are based on data collected during the 12 months prior to June 30, 2008. This means the recent tumultuous events in the financial industry hasn't fully affected these rankings.

You can see some effects, as Merrill Lynch dropped from 22 to 34, while HSBC dropped from 23 to 27. AIG dropped from 47 to 54, and Morgan Stanley dropped from 37 to 42. I'm a tech writer, not a financial analyst, but I think it's obvious these are either going to plummet or even disappear next year.

Among tech companies, Nintendo rose from 44 to 40, Yahoo! dropped from 55 to 65, and RIM made the ranking for the first time at 73, Dell dropped from 31 to 32, Apple rose from 33 to 24, and HP stayed put at 12.

Jez Frampton, Global CEO of Interbrand said:

“The Best Global Brands 2008 ranking is a reflection of the global economy – the current credit crisis in the U.S., the growth of emerging markets and the increased emphasis on sustainability are all key trends that resulted in brands rising or failing on the list. The increasing complexities of the global economy reinforce the importance of protecting and growing a brand. It is a company’s most valuable asset – and a far less volatile asset than others during a time of economic uncertainty.”