Reports that the advertising budget to promote the Windows Phone platform in the USA could reach as much as US$100 million have been rubbished by Microsoft watcher, Paul Thurrott. He says the budget is closer to double that.

News reports had suggested that AT&T, Microsoft and Nokia were collectively planning a US$100 million spend on promoting the Nokia Ace (Lumia 900) smartphone when it is announced at CES next week.

However, citing internal documents he has seen, Thurrott wrote that the collective spending power of all the Windows Phone suppliers would reach at least US$200 million - and that is just in the USA market.

On AT&T at least, he said that Nokia is outspending Microsoft 2-to-1.

Some of the marketing budget will go on sales promotions to encourage retail staff to push the handsets, reportedly offering sales staff US$10-15 per handset sold.