MS own the N3 IP, why aren't they pubishing their own game??

Because Microsoft feels that Konami has more experience in handling similar titles. It's pretty much the same situation with Square Enix and Infinite Undiscovery.

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Ninety-Nine Nights is a trademark of Microsoft Corporation.
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http://www.konami.jp/gs/game/n3-2/

Yep, it appears that MS owns the IP but they farmed out publishing duties to Konami just like they did with Infinite Undiscovery to Square-Enix.

Probably because the game is geared towards Japan and a Konami game would sell better. Also MS resources are most likely full with all the games coming out this year plus Natal work. MS also owns Crackdown and they're not developing it.

found a better answer

When Microsoft launched the Xbox 360 in 2005, one of its prime directives was to gain a substantive foothold in Japan. To do so, the publisher signed on a variety of high-profile Japanese game developers to create games targeted specifically at the island nation, games like Ninety-Nine Nights from Tetsuya Mizuguchi's Q Entertainment and codeveloped by Kingdom Under Fire studio Phantagram.

N3II retains the original's suffocating hordes of enemies.

And though Ninety-Nine Nights didn't fare particularly well with critics, Microsoft announced that it had tapped FeelPlus to develop a sequel for the Xbox 360 at the 2008 Tokyo Game Show. Today, Konami announced that it will publish the game in Europe this spring, with the game's North American release to follow this summer. Konami also redubbed FeelPlus' brawler as N3II: Ninety-Nine Nights.

N3II will be a direct follow-up to Phantagram's original, presenting a style of beat-'em-up action similar to Koei's button-mashing Dynasty Warriors franchise. Players can wade through hordes and hordes of enemies as one of five different factions, including humans, elves, and goblins. The five factions all have unique storylines, as well as race-specific skills and abilities. The game will also feature two-player online co-op, giving gamers a chance to team up to face down waves of enemies.

It's a smart move by MS if they don't want many in house first party developers.

Own the name, farm it to someone and take less risk in terms of paying for development, yet owning the name sake and getting some money from it without much investment.

It will most likely happen with PGR down the road to.

Konami is a bigger name than MGS in japan.

Does this have a US release date?

Yeah, Konami said yesterday that it will also release in Spring in the USA.

I need a actual release date.

The first one was decent.