The new US numbers are out now and they show the PS3 version of GTA 4 in the 8th slot -- just above Guitar Hero 3 (Wii version) and just below Super Smash Brothers: Brawl. It's also selling about half of what the 360 version is selling in the US.

How is this possible? The GTA franchise is Sony's home turf, their strongest franchise and biggest advantage from last generation. And in a few weeks Guitar Hero 3 for the Wii will probably be outselling it on a regular basis and the 360 looks like it may maintain a 2:1 sales lead, or nearly so, in North America.

Also, Mario Kart Wii and GTA 4 for the 360 are now neck-and-neck in sales, with Mario Kart Wii outselling GTA 4 for the 360 this week. Which game will end up on top at the end of the year?

Erm...

You mean this is 360s "home turf".

I would think Japan would be Sony's home turf actually. Also, based on VGchartz data, the 360 has over 11 million consoles sold in the US and the PS3 only has nearly 5 million, which ought to help explain your question.

I mean the GTA franchise is Sony's home turf. I'll update the OP to make that clear.  IT's a franchise that sold tens of millions here in the US alone for Sony last generation.

Yes, and it has a higher attach rate, but it has still sold to a large percentage of PS3 owners, and its sales are very far from poor

well 360 due to a year head start has around twice the number of units in NA compared to ps3, so it goes without question in NA 360 gta4 will be selling more

Microsoft secretly buys games and consoles from retail and sells them again to boost their numbers.

GTA4 Sales/Consoles Sold

PS3
1.8/4.91 = 37%

360
3.54/11.53 = 31%

Why is GTAIV selling so pooly on the 360 in NA?

It's because more Americans own XBox 360s.

Consoles sold ratio 11:5 thats more than 2:1
GTA4 sold ratio 3.5:1.8 thats just less than 2:1