We don't have the exact figures, but it's pretty clear Microsoft has pumped plenty of money into Windows Phone 7 in squeezing a few crumbs of smartphone pie out of the greedy hands of iOS and Android.
And now we know where that cash is coming from: Android. According to Citi analyst, a patent deal between HTC and Microsoft sees the Big M make $5 for every HTC Android phone sold.
Citi number-cruncher Walter Pritchard says it's very much in Microsoft's interest for HTC's Android portfolio to succeed because of the terms of the settlement that was reached in a wide-reaching patent dispute early last year.
Microsoft took HTC to task for numerous IP infringements in April last year, pointing to everything from the HTC user interface to the inner workings of the Android operating system itself.
With estimates that HTC has sold around 30 million Android phones so far, that's $150 million in Microsoft's back pocket - more than enough for some serious Windows Phone marketing.