Silicon Valley: Silicon Valley-based search engine firm Google, Inc, with a brand value of $66.4 billion, has overtaken Microsoft as the most powerful global brand, says the UK market research firm, Millward Brown Optimor in its latest annual ranking survey.

Microsoft, with a brand value of $54.9 billion is ranked third behind General Electric, which had a brand value of $61.8 billion.

Coca-Cola, for years the most powerful global brand, ranked fourth with an estimated valued of $44.1 billion.

The study, Brandz Top 100, by Millward Brown said that the search engine''s brand value had increased by 77 per cent since in the last one year.

Joanna Seddon, chief executive, Millward Brown, said that success stories from this year''s Brandz Top 100 demonstrated that winning brands leverage major market trends effectively to create business value.

"Strong brands are capable of extending into areas of opportunity to access new revenue streams and to help businesses respond to market changes," Brown said.

The ranking attempts to put a dollar value on a brand based on current and expected future earnings. The figure is generated from hard economic data as well as softer variables such as intangible consumer loyalty and perceived growth potential.