Analyst expects Microsoft's juggernaut to push US Xbox 360 console sales above 400,000 in September.

Halo 3 screenshot

Wedbush Morgan analyst Michael Pachter has delivered his latest research note to investors, predicting that Halo 3 will "sell over 3 million U.S. units in its first 12 days".

Pachter also notes that Halo 3 should provide Microsoft with a bona fide system seller.

"We expect the game to be a driver of console sales, and believe that Microsoft's unit sales for the 360 could exceed 400,000 in September, the highest figure for a non-holiday month since launch," said Pachter.

Pachter's estimates follow those of Lazard Capital Markets analyst Colin Sebastian who predicts that Halo 3 could bring in sales revenue of $200 million in the first 24 hours on sale.